How much fun can you have in black-and-white? As Jess Cartner-Morley explains, this isn't a look for the faint-hearted

Prime minister's wife adopts look made famous by former prime minister as Thatcher family dress in careful show of unity

It was a bold statement. Straightforward to the point of literal-mindedness, and defiant in its punchy message. What's more, it was an eyecatching feminine flourish among a sea of sombre suits.

Samantha Cameron's outfit for the funeral was a direct tribute to Lady Thatcher herself. She wore a gold silk blouse with a florid pussy bow. The pussy-bow blouse is a look which Thatcher made her own. Thatcher's other style signatures – the pearls, the handbag – are part of the broader lexicon of power dressing, but a pussy-bow blouse can mean only one thing. It is unmistakably a homage to the wardrobe of her Downing Street years.

Cameron has had a high-level career in the luxury fashion industry, and is an active ambassador for British fashion. There is no doubt that she has a sophisticated understanding of sartorial nuance, and knew exactly the impact a pussy bow would have.

A gold pussy-bow blouse is a notably upbeat choice for a funeral. But it is not informal: Thatcher herself proved it is possible to conduct serious state business while wearing one.

Until now, Cameron has used her wardrobe to send a message about a new, modern era of conservatism. She wears Zara shoes to party conferences, edgy British designers to state dinners, and trouser suits instead of wifely dresses. Which makes all the more striking her decision to draw such a direct connection between herself and this controversial figure.

Interesting, also, that with controversy simmering over the presence of the Queen at the funeral of a "mere" (as the BBC put it) politician, a politician's wife should put herself so boldly in the limelight. The pussy bow is a motif of Toryism, not of traditional mourning. Those who grumbled that this was a Tory state funeral might feel vindicated if the upshot of the occasion is the return of the pussy-bow blouse to newspaper front pages.

There were other style revivals at St Paul's. Most notable was Tory Power Hair, enjoying the most high-profile reunion since the Spice Girls. Lord Heseltine and Michael Portillo sported gleaming, swept back locks. Sir Bernard Ingham, Thatcher's former press secretary, reminded us that model Cara Delevingne did not invent the Power Eyebrow. Even Boris Johnson appeared to have employed a Mason Pearson for the big day.

The Thatcher family were dressed in a careful show of unity. The men wore morning suits, the women A-line knee-length black coats over matching dresses, with uniform 40-denier tights. Amanda Thatcher, her face shaded by a rather old-fashioned hat, the spotless soles of her shiny new Mary Jane sandals glimpsed as she curtseyed to the Queen, was impeccably sober. No Pippa Middleton scene-stealing here. The Queen, so rarely seen in black, looked rather marvellous in her black suit and pearls, a keen reminder to the rest of us of the power which can still be invested in the wearing of black if only one didn't fritter it away by slobbing around in black jeans.

In the context of ongoing debate over the level of the pomp and ceremony of the funeral, the clothes worn by other guests took on an added significance. Many could be seen to be treading a careful line which was respectful without being overblown. Men seated in the front row followed the dress code to the letter, wearing black waistcoats under their suits, but further west along the nave any dark suit seemed to fit the bill.

Among the women, there was a bounty of pearls. Diamonds are too flashy, unless one is the Queen, in which case a simple diamond brooch is a subtle reminder of status; pearls, being the precious jewel of the middle classes, strike the right balance. Furthermore, of course, Thatcher always wore the double-string of pearls she was given by her husband on the birth of their twins. Among the women on the front row – mostly politician's wives, media-aware and conscious that their outfits would be scrutinised – the hat style of choice was a shallow pillbox. A hat without a brim is ceremonial but not, as it were, state. (The style was also favoured by Thatcher herself in her early career, until her advisers decreed hat-wearing to be un-modern.)

To scan the audience during the service was to be reminded that the Britain of Thatcher's heyday was a less glossy, less polished, less camera-ready nation. This was how public life in Britain looked, back in the days before Botox and the fasting diet. Those guests who opted for glamour and baubles – Katherine Jenkins with an extremely foxy veiled hat, Cherie Booth with a Chanel handbag – were in this context the exception, while in most of 21st-century public life they have become the norm.

Eleven Guardian contributors give their verdicts on the ceremonial funeral at St Paul's Cathedral

'This season black and white is trying to be fun and to do that it has to subvert expectations'

The meaning of black and white should be clear. Isn't that what is intended by the phrase "in black and white", after all? Black-and-white clothing is an age-old signal of servitude and humility: think of a priest's robes as contrast to papal raiments, or a waiter's uniform in a smart restaurant as a counterpoint to the finery of the female guests.

It's not quite as simple as that, though. The uniform of a waiter and a man in a classic black-tie tux signify different things. And more than half a century ago the meaning of black as a colour evolved from melancholy of a fundamental nature (funerals) to include boredom as an affectation or lifestyle choice. Certain pieces of black and white clothing retain their meaning – a white dress for a bride is a tradition that shows no sign of shifting – while on a more muted level black jeans have somehow retained an air of rock'n'roll cool that no longer applies to blue jeans. But the sands shift.

One constant is that black and white means serious. This is why birth announcements come with a black-and-white photo of the newborn (also, babies can look blotchy, so monochrome or sepia are flattering in this respect). Conversely, breezy holiday snaps will be posted on Facebook in Technicolor (or the modern equivalent: X Pro II or Kelvin). A man in black tie is dressed to play the straight guy to a more gaudily dressed date.

But, this season, black and white is trying to be fun, and to do that it has to subvert expectations. The boldest route is to embrace Op Art stripes, chessboard graphics or mixed monochrome prints. This isn't a look for wallflowers: an outfit that is black and white yet gaudy in its pattern sends contradictory messages, so if having strangers staring at your outfit in a puzzled fashion is going to freak you out, avoid. (As someone who has strangers staring at my outfit in a puzzled fashion every Saturday, I crashed through that pain barrier a while ago.) You can bend the rules without giving the world a headache – a black trouser suit with a white stiletto, say, turns the landscape of a business suit (black suit and shoes, white shirt) upside down. Black and white: simple has never been so complicated.

• Jess wears blouse, £195, mywardrobe.com. Trousers, £185, by Kate Spade,020-7836 3988. Heels, £45, asos.com.

Photograph: David Newby for the Guardian. SHair and makeup: Dani Richardson using YSL Beauté.

Crystal-studded bodysuit with trompe l'oeil breasts and nipples is among costumes for Mrs Carter Show

As she embarks on the first dates of a sellout four-month world tour which takes in 42 cities, Beyoncé's status as the world's most powerful female star has never looked more assured. But controversy over her risqué stage outfits is causing cracks to appear in her claim over another lucrative title – that of America's sweetheart.

One outfit in particular has proved divisive this week. A crystal-studded bodysuit hand-painted with trompe l'oeil breasts and nipples, designed by the New York label The Blonds has raised eyebrows. The deliberately provocative outfit has a distinct showgirl feel and has prompted commentary beyond fashion circles. The US sociologist Dr Hilary Levey Friedman told Fox News: "You have to wonder what one of Beyoncé's biggest fans, Michelle Obama, would tell her daughters about this outfit."

So far, any kind of "crystal-nipplegate" scandal has yet to emerge. But it is conceivable that following the furore over lipsynching at the inauguration, and a chilly statement from the White House distancing the administration from the trip taken by Beyoncé and her husband, Jay Z, to Cuba, the Carters' position at the heart of the presidential court has been weakened.

Meanwhile reaction inside the fashion world has centred on the costumes' aesthetic value. Designers Phillipe and David Blond told Womenswear Daily that their outfit, which was intended "to give the illusion of being covered in crystallised honey", was handpainted on to a bespoke bustier suit for anatomical accuracy and then "hand-embroidered with approximately 30,000 Swarovski crystals that took over 600 hours to apply". The designers cited Tamara de Lempicka's paintings of the female body as a reference – although some observers were struck by a connection to the pneumatic nudes of the cartoonist R Crumb.

It is unlikely that the star's PR machine will be ruffled by the week's sartorial debate. Perhaps in a deliberate attempt to provoke media attention and chatter there is a stark contrast between the stage wardrobe – which takes Vegas showgirl sequins, hotpants and bare thighs as its central themes – and the demure persona suggested by the tour's moniker The Mrs Carter Show.

Fashion watchers have noted that Beyoncé has opted for glamour and impact over fashion kudos: while she could command bespoke outfits from any designer on the planet, she has worked with many lesser-known names. Designers who have contributed to the Mrs Carter wardrobe include Ralph & Russo, who made a white crystal and pearl bodysuit with peplum ruff in which Beyoncé opened the tour. Vretto Vrettakes, a Greek-born Royal College of Art graduate, has contributed a shimmering blue catsuit to the tour wardrobe. Dean and Dan Caten, the designers behind the Italian label Dsquared2, well known on the Milanese catwalk circuit but not quite household names, have also been involved.

One A-list exception is Givenchy's Riccardo Tisci, who designed a black sequinned leotard and matching animal-eared riding hat, which riffs on the Playboy Bunny aesthetic. Tisci is a co-host, with Beyoncé, of next month's Met Ball at the Metropolitan Museum in New York, an event considered to be the most exclusive night on the international fashion calendar. The inclusion of the Givenchy brand assures that the Mrs Carter look retains the singer's place in fashion's upper echelons.

Despite the controversy over whether the look is too risqué or not cutting edge enough, the real measure of the success or otherwise of the Mrs Carter tour wardrobe may come later. Over recent years stage costumes have garnered an interest beyond the life of a particular tour or album. Exhibitions of musicians' most iconic stage looks have proved increasingly popular. The V&A's current David Bowie exhibition – to which fashion is central – is doing brisk business, and although it is unlikely that Beyoncé's crystal bodysuit will ever earn the status of the metallic Ziggy Stardust bodysuit designed by Kansai Yamamoto in 1971, in terms of the lasting impact of a tour wardrobe, the basic tenet is: the more controversial, the better.

Clothing sales at M&S have fallen for the seventh quarter in a row. What's gone wrong? And how can it be put it right? We asked experts and fans to come up with an instant rescue plan

Kirstie Allsopp, TV presenter, also designs a homeware range for M&S

I'm very proud to have a range in Marks & Spencer, although I think I can be honest about what I feel. I used to buy a lot of clothing from M&S – I've always been a fan, and I adored their Autograph range [famous fashion designers were brought in to collaborate on collections]. There are fashion designers whose stuff I wouldn't buy at the top end, but who did a diffusion line for Autograph when it first started, and I have some pieces from that range that I still wear. But M&S doesn't have that any more.

When I talk to the girls at work – many of them in their mid- to late-20s and on low incomes – they tell me they shop at Primark. I don't see them buying anything from Marks & Spencer. It has become about the food, which out-cools and out-sexes the clothes. Something, somewhere got a little bit lost.

I trust Marks & Spencer, but I don't have the sense any more that I will make a real discovery. My fashion advice mainly comes from weekend newspaper supplements, and I don't see a lot of M&S stuff in them. I know they do makeup, shoes, accessories – but I can't remember the last time I saw something in a magazine and thought, "ooh", and then saw it was from M&S.

M&S can get its position back. The staff have a great attitude, and the company as a whole is a good one. I just think its womenswear has lost its edge.

Jess Cartner-Morley, Guardian fashion editor

There is one straightforward factor contributing to M&S's woes. There is no one manning the tiller, fashionably speaking. The current collections fall between two reigns: they were conceived after Kate Bostock left last year, but have not been steered by her replacement, Belinda Earl – her influence will not be seen until the first autumn ranges land at the end of this summer. I have observed the dynamics at M&S for some time, and it strikes me that a healthy relationship between the CEO and the person fighting fashion's corner is key to good product. It will be fascinating to see what impact Earl has next season.

In part, the problem for M&S is that the competition has got so much better. The British high-street shopper is now thoroughly spoilt. Once, M&S filled a gap between fast fashion, which was cheap as chips but shoddily made, and the stodgy, elasticated-waistband fare of department store fashion. But the fast-fashion market has improved its production values, while a new category of grownup high street stores, such as Reiss and Cos, has emerged. M&S, once front and centre of our clothing consciousness, has to fight for airspace. There has been a tendency to fight for attention by filling the rails with "trend-led" clothes, which are often successful in winning media attention, but don't deliver strong sales on the shopfloor.

As a nation, we still identify strongly with M&S. It is a part of Britishness in a way no other brand is. Each of us has a an opinion on what M&S should be selling, just as every football fan has a view on the team their manager should field. Here's my own tuppenceworth on how M&S should alter their offer: by refining the colour palette. Walk on to the womenswear floor and you find yourself in a hectic, multicolour world. Less pink, yellow and red, and more bottle-green, navy and off-white would instantly update the environment. Yes, you might annoy the odd customer who was hellbent on fuschia, but you can't please all of the people all of the time.

The silver lining is that many women don't realise how much good stuff there still is in M&S. (I'm talking flagship stores. Sorry, provinces.) Recently I've bought a phenomenal leather pencil skirt with a gold zip, beautiful fabric and construction, for under £200, and a cream silk blouse with coral pocket borders that looks like it came from Paris for €200 rather than Oxford Street for £45.

Jenny Eclair, comedian and writer

I have had the almost overwhelming desire to snatch things out of the hands of women who are hovering around the Per Una stand, particularly when they are going into Per Una overdrive and getting everything to match. Per Una is the heroin of middle-aged women's clothing. You start off with just a little bit – maybe a waterfall cardigan in jade with some beading around the neckline. Snazzy. And before you know it, your wardrobe is bulging with appliqued skirts and embroidered jumpers. I think it's for those women who have completely lost their inner rock chick and have to find another path.

Marks & Spencer could very easily get it right if they kept it simple. Where they go wrong is when they start to ornament things with frills or beading. What people want is to go to M&S and buy a good mac, a good white shirt, a denim skirt, a jumper, maybe in cashmere. With their colour, they go a little bit lurid – I sometimes go in and it makes my teeth hurt. I do buy from Marks. I buy V-neck jumpers, and black cardigans.

There is a great demographic of peculiar women who can't wait to get to the appliqued-skirt time of life. There is still an M&S die-hard population – you see them in market towns. It's a shrinking breed of women, but I think Marks are still loyal to them.

I gig a lot, and M&S food has completely revolutionised touring, because they're at motorway service stations now. The days of Ginsters sausage rolls are over – now you can get chargrilled squid if you so desire. But I do think somebody needs to take a very stern hand with the clothes. They need to get some stylish middle-aged women, people like India Knight, who could actually just boss them around a bit. They have a terrible tendency to go for lilac clothes. I'd love to go on some kind of panel, giving a thumbs up or down as people were paraded in front of me.

Richard Perks, director of retail research, Mintel

There are two main drivers for M&S – womenswear and food. The food is doing well, but the problems are with the womenswear. They did the right thing in splitting it up into different sub-brands, but those brands are now insufficiently differentiated. They're also too "old". The great thing about Per Una when it launched was that it was young fashions engineered for older customers, but the "young" look has gone. Historically, you were dragged in there by your parents and swore never to go in again, and then around the age of 30 you happened to go in and thought, "Oh, that's quite good." But it doesn't seem to be picking up those younger customers now. Debenhams is sitting where M&S should be, and does a good job, because its brands are differentiated.

There's a failure to understand what older people want. Sometimes you feel the merchandise is bought by a 25-year-old [M&S buyer] who has a caricatured granny in mind. Older people don't want to be sold down to. That is why Per Una did so well, because it looked young. That's what they've got to get back to.

M&S always did well in a recession – people went back to it because it was good quality and value. In boom times, it tended to over-engineer its products and they got too expensive. So it would have a bad start to the recession, but it would simplify its products, make them cheaper and clean up – that hasn't happened this time. I think Marc Bolland has to take responsibility for that.

Lead times are long – however much you like the idea of fast fashion, most things have to be planned in advance. Belinda Earl [former chief executive of Debenhams and Jaeger] joined in September, and she couldn't really have any significant impact until autumn/winter this year. Thing have drifted; they need to take those sub-brands and give them their own personality.

Lynne Franks, PR expert and champion for women's empowerment

I have bought from Marks & Spencer. Some of the basics are still pretty good and over the years they have had wonderful things – great cashmere, good knitwear. But I went in this season and there was nothing there I wanted to buy. I don't find it enticing, and that's a shame. There are always some good bits, but generally the shape is not right, the cut is not right. What would I suggest they do? Get a new design team.

A lot of women who are not young buy fashion, but wouldn't shop at M&S. I don't think M&S has to go younger, just do better stuff. Women of my age, 50-plus, have money to spend and love fashion. We grew up in the 1960s, and don't want to look like frumps. M&S could really take ownership of that market in the high street, but they have to realise the 50-plus woman today is much more stylish, and knowledgable than their mothers probably were.

Kim Winser, former chief executive of Pringle and Aquascutum, and director of womenswear at Marks & Spencer until 2000. Now runs Winser London

It's all about passion for product. That's what M&S has to turn its attention to – get back to really good, beautiful, quality products. I buy food from M&S, but not clothing – I haven't found that combination of fashionability, style and quality.

They do a number of different brand names – too many. By focusing on a few, they could use each brand to focus on a certain customer group, and gradually build up the value of that brand to that group – they will begin to love it and trust it and know it's for them.

When I was there we launched Autograph. It was about bringing in some of the best designers in Britain and capturing what they were good at. The designer collaborations can work, but only if it really does represent what that designer is famous for.

I don't think it's about the size of the company, I think it's about the people. There are too many excuses about business and bureaucracy, but the company is run by people, and I was definitely left to run womenswear, which at the time was a £2bn business. I was given that responsibility and accountability. I loved it, and as a team of people, that was one of the reasons we had market-share growth, because we really did love the customer and the product. So it can be done, whatever the size of the business, but I think it depends on the people.

Lifestyles change, and it's about a company constantly innovating, looking at what's happening and also predicting what's going to happen. To do that, you have to be absolutely in tune with your customer and what they want, and focus on what your brand is good at. I'm looking from the outside now, but that's where M&S was always a very successful business, because it put the customer first.

Susie Lau, fashion blogger for Style Bubble

M&S lacks focus in its product. It tries to cater to many different types of women in its various ranges, and doesn't do one thing very well. M&S has come up against companies that do good-quality, timeless fashion with a wider appeal – stores such as Uniqlo or Cos. M&S was once renowned for being the store where you bought your first bra, for instance, but there are so many more options now.

We have a nostalgic attachment to M&S, but I don't know many people my age who go in there. The only time I do is when I'm shopping with my boyfriend's nan. I do look at its lookbooks [the catalogues produced for the fashion press], and I wrote about a selection of M&S stuff for the Guardian a few months ago. It does have nice products, but it has a problem communicating that within its stores. The outlets are very rigid, they don't entice you in as a fashion store. Even if they have good products, they're buried behind the food store, or you have to go through various ranges to get to where you want.

I don't think M&S needs to position itself as a fashion-forward store. It's more about finding what it does best – it's really strong in cashmere, in basics – and concentrating on that rather than trying to cater to everyone's tastes.

This season it's all about bright accessories - lime patent heels and luminous yellow clutch bags. Jess Cartner-Morley shows you a few shining examples

'Hard on the nude heels of the Kate Middleton effect, we have the backlash'

Poor K Middy. Not only has the popularity of the duchess herself already been overshadowed by devotion to HRH the Baby of Cambridge, but her favourite shoes have gone out of fashion. Life can be so cruel.

Hard on the nude heels of the Kate Middleton effect, we have the backlash. Last year, the skin-toned pumps she wore at every opportunity were the toast of the high street. The leg-lengthening properties of a high heel in a shade that matches your bare legs were praised the length and breadth of the kingdom. And they go with everything. What's not to love?

This year, we have a mutiny on our hands. Or, rather, on our feet. The trouble with those nude heels is not that the leg-lengthening effect isn't real, or that they don't go with everything. Both are absolutely true – and that's the problem. The nude shoe is just too easy on the eye. Too well behaved. Too anodyne. A bare leg in a nude shoe looks a little like a Barbie limb, frozen into a pert, high-heeled stance. At the risk of sounding like the Hilary Mantel of the fashion journalism world, the Kate Middleton nude heel lacks flavour, let alone bite.

Times have moved on, and fast. This summer, you can walk into any high-street store and find a shoe to match your favourite-colour Jelly Baby. Bags, too, have gone bright: where traditionally the leather goods industry has liked to signal the heritage of its handbags through an emphasis on black, oxblood and tan, this season's It bags are as likely to be raspberry, petrol blue or zesty lemon.

The bright accessory is effective for the exact opposite of the reason that the nude shoe is effective. A nude shoe allows the observer's gaze to roll from pretty face to unobtrusive toe with no snagging. A bright accessory, on the other hand, is a curve ball, catching your eye at unexpected angles. It works, this season, because the silhouette and design of accessories are having a sleek, pared-down moment – single-sole pumps, slender, boxy clutches – that lends itself to bright colour. Poor old Kate, getting the blame. Maybe she can cheer herself up with a nice new pair of shoes.

• Jess wears suede ruched-front dress, £550, burberry.com. Pointed court shoes, £365, and clutch, £550, both jimmychoo.com.

Photographer: David Newby. Hair and makeup: Dani Richardson using YSL Beauté.

Rihanna, Cara Delevingne and Taylor Swifts all wear varsity jackets, but Jess Cartner-Morley picks out some examples that cross the generations

Who better than a pop star to help us find the best, most cutting-edge bargains at Bicester's new discounted designer popup boutique?

Rita Ora isn't quite the kind of celebrity you expect to find at Bicester Village. Middletons shopping for cashmere are two a penny; but shouty pop upstarts wearing Roksanda Ilincic with matching lipstick, and buying up Henry Holland neon tweeds? Not so much.

Rita was at Bicester for exactly the same reason as myself, Caroline Rush of the British fashion council, blogger Susie Bubble, and pretty much everyone in the fashion industry: the opening of the latest British Designer Collective pop-up store, selling recent catwalk pieces by London fashion week stars including Roksanda Ilincic, Jonathan Saunders, Preen, Mary Katrantzou and JW Anderson at knockdown prices.

For those sceptics who haven't run to Marylebone to catch the next train and still need to be convinced to make the trip, here's why the BDC is so much more than a sale shop. The past few years have been a golden era for British fashion and the new boutique has been curated by Yasmin Sewell, who has cherrypicked the best pieces from recent years (and yes, each is available in a range of samples, not just one 6 and one 8). There are Jonathan Saunders' spongey knits, draped Roksanda Ilincic gowns, and showstopping Nicholas Kirkwood shoes.

Rita turns out to be a fun shopping buddy. "I'm so happy to be here! Even though it's so early. I never get up this early!" (It was 11am. Pop stars, bless 'em.) We elbowed our way through the crowds, riffled our way through the rails, and hereby bring you the Ora Oracle: Rita's top seven picks from the British Designer Collective popup store:

1. Mary Katrantzou silk cocktail dress, with heart design and formal-garden print, £1,230

Rita says: "It has a seductive, Eve-like vibe that I love."

2. Lucas Nascimento structured purple shift dress, £250 (original price £1,380)

Rita says: "This is awesome. I love that the construction and the fit are so precise and structured, but the fabric is kind of crazy. That's quintessentially British fashion.

3. Roksanda Ilincic short fuschia silk organza dress, £600

Rita says: "This is amazing. I'm having a Beyoncé moment after seeing her perform the other night, and this could fit the bill.

4. Richard Nicoll maxi-dress in pink crepe de chine/georgette. £130 (original price £1,300)

Rita says: "This is cute! I could perform in this. I want it!"

5. JW Anderson perforated leather pencil skirt, £322

Rita says: "I luuuurve JW and I love good leather. I would feel very sexy in this skirt. It's so minimal but has a youthful feel which makes it really cool. I'd wear it to, like, an incredible dinner where I wanted to really impress someone."

6. JW Anderson 3D cable-knit sweater, £313

Rita says: "The only reason I'm not buying this is because I already have it!"

7. Jonathan Saunders red textured skirt, £276

Rita says: "I love the colour. I'm a big fan of red. I'd wear a matching lipstick."

While plenty of trends are self-evidently for the under-30s, others become age-inappropriate by association

Rihanna wears a varsity jacket, and Cara Delevingne, and Taylor Swift. These women are 25, 20 and 23. Oh, and Romeo Beckham got papped in his the other day. He's 10.

So you see the problem: the varsity jacket has gone all ageist on us. This is an unexpected development. While there are many trends that are self-evidently for the under-30s – those "pokey" shorts with pockets longer than the legs; anything with an amusing animal face on it – others become age-inappropriate by association. The varsity jacket is one of those.

You may know the jacket I'm wearing as a baseball jacket, or a letterman jacket, depending on vintage – your vintage, that is. Those of us (ahem) old enough to remember Flip in Covent Garden – an 80s temple to baseball jackets and Levi's – might struggle to reclassify this style as a new trend. The rule goes that if you're old enough to have worn a trend first time around, you should bow out of its revival. There was some logic to that when fashion moved at a slower pace and a look took decades to come back. But now, when fashion careers from trend to trend at such breakneck speed that it is liable to come full circle within 18 months, the old law is trickier to enforce. Were I to adhere to it, every hemline between midi and micro mini would be off limits, as would every decade from the 1920s to 1990s. I'd be left with a stark choice between hobble skirts and dress-down Friday chinos.

Therefore, I've decided I'm not really prepared to cede the varsity jacket to the kids. There should surely be some zones within fashion that are permanently accessible to all, not available to be land-grabbed by the latest generation of hipsters. We need a sort of right to roam, but for style rather than countryside. A green belt of clothing options that we know will always be there. Into this category I would put the varsity jacket, along with white T-shirts, jeans and Dunlop Green Flash.

It's only fair. After all, not all of us are young enough to have the option of wearing pokey shorts and a zany animal T-shirt.

• Jess wears varsity jacket, £400, by Oak, from net-a-porter.com. T-shirt, £68, by Lulu & Co, from asos.com. Jeans, £229, by J Brand, from fenwick.co.uk. Shoes, £59.99, mango.com.

Hair and makeup: Dani Richardson, using YSL Beauté.

Talk about a challenge. The Met Ball is fashion's smartest party – and this year, the theme was punk. Here's our guide to who ripped up the red carpet, and who was a rebel without a cause

Princesses of punk: those who got it right

Carey Mulligan

Carey's ice-cool take on punk chic makes everyone else look a bit try-hard and overdone. The cutouts on this Balenciaga catwalk dress are fittingly angular, rather than cheesily peekaboo. The safety pin and the slicked hair are nicely edgy, balanced by the cocktail hemline and elegant shoes. As for the scowl, and the cool girl's disdain for the lipsticky trappings of an evening bag: this is not just fashion, it is method acting.

Cara Delevingne

Ultra-plunge long gown with a pap-friendly glimpse of sideboob: yawn, right? Nope, not when Burberry rustle you up a special number with the top half armoured in tiny gold spikes, which might be a little hedgehoggy on a more rounded body but which combine with that minxish Cara attitude and insanely willowy figure to make punk magic. The piled-on earrings, rings and necklaces and bad-girl plait are all working here. They don't call her the new Kate Moss for nothing, you know.

Sarah Jessica Parker

It's the first rule of parties: go hard or go home. SJP has gone hard, with a gold and black Philip Treacy mohican headpiece and thigh-high tartan velvet boots accessorising her Giles Deacon dress. This grand silk taffeta ballgown in a splashy anarchic print has a punk soul, taking the fabric and silhouette typical of Upper East Side eveningwear and subverting it. If we have a slight quibble, it's that the tan is verging on MIC.

Sienna Miller

Who would have predicted that Burberry would be so good at red-carpet punk? Sienna's punk biker and bleach-white dress are a mix of hardcore attitude and clean, simple silhouette and colour palette which totally works. Also, we always love to see a girl get her post-baby party mojo back, and if we're not very much mistaken she's got the look of a girl about to hit up the cocktails. One problem: so matchy-matchy with Cara D that, side by side, the effect becomes ever-so-slightly Little Mix.

Anne Hathaway

A true movie star knows how to use the red carpet to make a statement, and that's what Hathaway did in vintage Valentino. First, she turned that poor-little-me Les Mis urchin cut into something vampish and edgy by dying it Debbie Harry blonde. Second, she showed how incredible her va-va-voom body is when she's living on the Fantine diet of teaspoons of baked porridge. Third, she showed that being upstaged by her own nipples at the Oscars has in no way cowed her into making safe fashion choices. Respect.

Carine Roitfeld

The front row's very own Iggy Pop lookalike is the true punk of them all, of course. Not for Carine the box-ticking safety-pin/stud approach. Roitfeld is the only A-lister rebel enough not to turn up in some version of an evening dress: instead, she wears a Givenchy sweatshirt with a floor-length, polka-dot sheer skirt. Best of all is the cartoon-pyjama Bambi cartoon motif, which – along with the signature undone hair and makeup – makes Roitfeld look as if she's spent the afternoon lying on her hotel bed watching DVDs and eating popcorn, rather than being primped into oblivion in a salon.

More chaos than couture: those who got it wrong

Madonna

Oh, Madge: this should have been your perfect invitation. Dress up. Dress Punk. Show them how it's done. No need to get some minion to call the fashion publicists because you already own this look. So maybe it was over-confidence, possibly it was the fishnets, perhaps the tartan. But somehow the elements conspired to make her less Givenchy more Dragon's Den. Worst are the cerise shoes, which suggest Madonna's punk is now studied rather than natural.

Beyoncé

No matter how many times I look for the good in Beyoncé's dress I keep coming back to the fact that it looks like the bedlinen from some corrupt regime dictator's pad. Worse: it's downright unflattering – on Beyoncé, for goodness sake. Even the intriguing fact that matchy-matchy thigh boots and elbow gloves bring chaos rather than harmony to the look can't rescue it. Bey's image will get over it, but it isn't reflecting well on the usually faultless Riccardo Tisci of Givenchy is it?

Kim Kardashian

Frankly, with the passive-aggressive peony print, the high neckline and the pray-that-they're-gloves-and-not-sleeves, it's tricky to see what's what: where does the bump begin and end? Even so, it's hard not to be charmed by a woman who loves fashion so much that she refuses to let her pregnancy dictate her wardrobe. Why should she roll over in a wafty empire line, eh? It's another Givenchy, which suggests that Tisci was deliberately aiming for the chaotic end of the dressing spectrum. Too much of a coincidence if not, right?

Florence Welch

Legend has it that when the ravens leave the Tower of London, disaster cometh. So the fact that they all showed up on Florence's Met dress should make us all a little fearful, no? She looks agitated – but then feathered boobs don't make for a relaxing night and nor does a fringed leather cape which pretty much demands you spend the whole shebang with your hands on your hips. The down hair and black nails conspire to make the look a bit Gothic Cowgirl. Givenchy again. Just sayin'.

Katy Perry

This dress isn't as mad as it thinks it is, which is kind of the problem. The Dolce and Gabbana catwalk look does make the singer look like a walking, sparkling pre-Reformation rood screen and the crown headpiece has a touch of the Courtney Loves about it. Which is mad and punkish in theory, but on Perry – who is a little "I'm a bit mad me" when it comes to her wardrobe anyway – the overall effect is a bit flat. On someone more classy, this could have been Punk. Maybe.

Debbie Harry

You would have to be heartless not to want this to work, but blind to argue that it did. What with the Vegas casino bag, the jacket worthy only of a Britain's Got Talent contestant, the Kensington Market shoes and the novelty Ladies' Day headpiece, Harry's look is chaotic in the extreme. Her red-carpet offering silently sums up the enormous gulf between the reality of living the punk dream and showing up at fashion's poshest party and looking like a high-end punk princess. Love that she kept the RayBans on though.

Misread the invitation: those who played it straight

You've got to be in it to win it, girls. It's all very well having your own personal style and all, but showing up at a gala to celebrate the
legacy of punk in a polite little frock is, frankly, a bit rude. Show them
Sex Pistols some respect, surely. Sure, Gwyneth's dress has racy sheer
panels, but she's GP – she doesn't leave the house without a sheer panel,
so this doesn't even count as trying. Jennifer Lawrence reprises her Oscar triumph, without considering that "if it aint broke don't fix it" is about
as anti-punk a motto as it gets. Kate Upton is all just-another-red-carpet
and there's an Olsen in a vintage dressing gown AGAIN. What about hostess
Anna Wintour in floral, floor-length Chanel? Hmmm. Well, I guess it's her party, and some people don't need safety pins through their ears to look
terrifying.
JCM 

Every summer has a new take on the deconstructed shoe, and 2013 is all about the two-strap sandal

'Every summer has a new take on the deconstructed shoe, and 2013 is all about the two-strap sandal'

There is a lot to be said for the judicious flashing of a little flesh. A few inches of skin can transform a look that would otherwise be dowdy. This is not only about sex appeal – it's about making a softer kind of human connection. A glimpse of skin humanises an outfit. (See: the difference between a man in a formal cuffed shirt, and that same shirt with the cuffs rolled.)

But overuse of the lowest common denominator version of this technique, for lowest common denominator purposes, gives the flashing of flesh a bad name. It starts with the hitching up of a school uniform skirt; a decade later, it most likely involves unbuttoning a button or two on a blouse. As a knee-jerk reaction against this, designers who want to be taken seriously will swathe their mannequins in reams of black fabric. There is nothing saucy about rolling up a sleeve, but it has an impact. Try it: stand in front of a mirror in trousers and a jacket, and push the sleeves up to your elbows. See?

The other route for non-slutty flesh-flashing is a bare ankle, and an almost-bare shoe. Summer shoes are an opportunity to harness the impact of skin without lifting a hemline or undoing any buttons. A nearly-naked shoe is not as butter-wouldn't-melt as baring a forearm, because legs are never entirely unsuggestive, and neither is toe cleavage, but neither is it as loaded as baring your shoulders.

Every summer has a new take on the deconstructed shoe, and 2013 is all about the two-strap sandal. The two-strap is where minimalism meets ice-cream weather: simple and clean-lined, with a strap over the ball of the foot and another around the ankle. The obtuse upside-down shoe architecture of recent summers – ankle boots with peep-toes, for instance – are a thing of the past. A popular twist on the two-strap is for the ankle strap to be a contrasting shade. Cute touch, but make it work for you: for instance, a nude ankle strap with a black toe strap will be far more flattering for your leg than the other way around.

Not, of course, that allure is the point here. Just a simple human connection. That, and an excuse to buy a new pair of shoes.

• Jess wears top, £39.99, and heels, £29.99, both zara.com. Skirt, £875, by Michael Kors, from net-a-porter.com.

Photograph: David Newby for the Guardian. Hair and makeup: Dani Richardson using YSL Beauté.

After years of falling clothes sales, new collection is make or break for M&S boss Marc Bolland

The most significant detail on the first womenswear range overseen by Belinda Earl, the new style director at Marks & Spencer, isn't the nod-to-Celine sorbet pink of the £85 coat that will hit stores in August, or the very-Victoria-Beckham just-below-the-knee-length dresses, or the on-trend kilt-styling of a tartan skirt.

In fact, it isn't visible at all, until you look at the inside of the clothes, and find that the overlocked seams usual on mass-produced clothing, and used by M&S until now, have been replaced by French seams in which the raw edges have been fully enclosed. The bold fashion message on which Belinda Earl is pinning her hopes of turning around the fortunes of Britain's biggest clothing retailer is about quality, not trend.

Earl's decision to pursue higher standards rather than high fashion is a big moment for M&S. While rivals Next and Primark are growing their sales, M&S is struggling – and its chief executive, Marc Bolland, hired three years ago with a £15m golden hello, is on the ropes.

M&S's clothing sales have been in decline for almost two years and if these new ranges don't fly off the rails his job will be on the line. Shareholders have given him until this winter to show his turnaround plan can work. There have even been rumours that an overseas buyer, possibly from the Middle East, will move in on the business.

Last night, the retailer revealed the collections to City analysts. Their reaction was just as important as that of the fashion press, which was given an early view. "We spent months in focus groups talking to customers," said Earl, "and the message was very clear. Women want quality, and they are encouraging us to reassert our leadership in bringing that to the high street. Often with focus groups you have to spend a long time unpicking the findings to work out what people are trying to say, but what was remarkable was how consistent the message was. Of course they want style, they want to look modern and relevant – we all do these days. But they still care about quality."

Earl, the former head of Debenhams and Jaeger hired to breathe new life into the ailing M&S clothing business, selects as her personal favourite from the collection an off-white single-breasted cashmere coat. At £229 it is far from cheap, but with the quality of fabric, fit and finish bearing up well in comparison with designer coats priced in five figures, it represents value for money for a customer prepared to invest.

The premium Autograph range, which had shuffled confusingly close to the main collection out of fear of higher price points, will now be premium once again: "Three-quarters of the fabrics in Autograph have been upgraded," says Earl. Cashmere in the main collection has been upweighted by 9% – but the price will be lowered by an average of £4 an item by ordering more and selling cashmere in more stores.

Bolland's future is now in Earl's hands – and those of the former head of the M&S food business, John Dixon. The store's upmarket food range, unlike its fashion, has been performing well. In January, Bolland also hired a new head of lingerie – Janie Schaffer from US chain Victoria's Secret – but she quit last month after falling out with Bolland.

In an industry driven by a constant desire for newness and a dizzying merry-go-round of trends, relying on relatively under-the-hood tinkering to turn around a crisis of the scale of the one facing M&S – which has reported a fall in clothing sales for seven consecutive seasons and is set to unveil a second consecutive year of declining annual profits next week – is a brave move.

But Earl insists the strategy "plays to the strengths of M&S. The quality of the shopping experience – from the shopfloor to how the clothes last – is what our heritage is all about. It's our DNA."

At ground level, the way the clothes are displayed is being updated to reflect how women now shop. There will be more outfits on mannequins, showing outfit ideas, and fewer crowded racks. "Three weeks ago we launched a 'Fashion Academy' so that the fashion messaging behind the collections is explained to the sales assistants, so that they can help customers."

Behind the scenes, M&S is trying to update its out-of-date distribution systems, which still rely on shop assistants counting clothes on the shop rails to assess stock levels. Three giant new clothing warehouses are being built so that online orders don't have to be gathered from 50 warehouses around the country before they can be sent. But the new behind-the-scenes systems won't help M&S if shoppers don't like the clothes.

Earl has overseen a leaner edit of catwalk trends. There are fewer pieces directly inspired by catwalk standouts, and more items designed with "wardrobe-building" in mind. "Our prints had become a little garish," admits Frances Russell, trading director for M&S womenswear, "so we have toned them down a little this season. We are thinking in a holistic way about what the customer already has in her wardrobe – monochrome pieces from last winter, for instance – and building on those."

Functionality and fit are as central to the notion of quality as fabric. "High heel tights" with a gel pad in the ball of the foot are a genuine lightbulb moment, while a "no-peep" white blouse with added buttons is a no-brainer. A washable silk blouse for £60, from the Autograph range, is a sound investment.

Success in womenswear is vital for M&S, because giving women a shopping buzz has a "halo effect" on homewares, childrenswear, food and menswear. Earl aims not only to shore up the traditionally strong categories of trousers, knitwear and underwear but to extend reach into coats and dresses, both of which are strong in this collection.

It remains to be seen whether customers deliver on their promise to prioritise quality over a fast fashion fix. But if they do – and it's a big if – this collection could be a high street gamechanger.

The winner of this season's Outstanding New Fashion Name is the origami skirt. It is a hybrid of two established looks, namely the pencil-skirt-with-split and the wrap skirt

'The origami skirt hits that oh-so-buyable sweet spot: it is a slightly altered item, with a name that makes it sound more daring than it really is'

OK, I'm calling it. The seasonal contest for Outstanding New Fashion Name is hereby declared over. And the winner is the origami skirt.

The origami skirt hits that oh‑so‑buyable sweet spot: it is a slightly altered but not entirely unfamiliar item, with a name that makes it sound more thrilling and daring than it really is. The origami skirt is a hybrid of two established looks, namely the pencil-skirt-with-split, and the wrap skirt. From the pencil-skirt-with-split, it borrows the form-fitting silhouette with the suggestion of extra leg (and perhaps extra licence) that the split lends. From the wrap skirt, it borrows a slightly more avant-garde, architectural silhouette.

The end result is a flatteringly shaped skirt whose split manages to seem precise, clever and rather exotic. The fun name adds the finishing touch.

What's more, origami is more than a silly name. The Preen skirt I'm wearing here really is folded, rather than snipped. Behind the split is a second layer, a snakeskin-printed thigh-veil. This is genius, because it solves the age-old practical issue with a split skirt, which is that a split that looks positively demure when viewed in the mirror of a changing room takes on a quite different character when you sit down on a train, or in a meeting room, and the glimpse of thigh turns into an eyeful.

One of my pet hates is clothes that have you constantly fidgeting with them. Those kind of clothes are distracting in the very worst way, and it is simply not possible to look chic and elegant while tugging at your hem.

The best foil for an origami skirt is a top half that is all straight lines and symmetry – a buttoned-up shirt or a simple crew-neck T-shirt. Anything floppy or floaty will kill the impact, so that the overall impression is messy rather than avant-garde. Simple flat-soled shoes are also important, rather than anything bulbously platformed or elaborately laced. Origami demands crispness, see? That's why it's not just rather a good look, but rather a good look with a very good name.

• Jess wears shirt, £470, by Roksanda Ilincic, and skirt, £868, by Preen, both matchesfashion.com. Heels, £42, asos.com.

Styling: Melanie Wilkinson. Hair and makeup: Tonee Roberio using Mac Cosmetics.

Stephanie Phair, MD of The Outnet, the discounted little sister of Net-A-Porter, tells us what savvy online shoppers should add to their basket this summer

You might expect the party line from The Outnet, the discounted previous-season little sister of Net‑A-Porter, to be that women want classic, timeless pieces. Quite the contrary: what Stephanie Phair has learned from the site's success is that "trends stick around longer than you'd think. When a good idea comes along, designers will play with it for several seasons."

Right now, soft pink is hot news. "Anything in that colour is flying," Phair says. "And that's a key colour for next season." Occasion dressing "for weekends away, and wedding guest outfits" is how many Outnet customers shop. "And the benefit of coming to a multibrand retailer is that you might start by viewing a brand you know, but end up finding something fantastic by a label you'd never have thought to look at." Phair's number one tip for online shopping: always filter by size. "In particular, on our site, which doesn't have every size in every item, this really speeds things up, so your hit rate is much better."

Sketch out a capsule wardrobe for summer 2013? "I'd start with a dress, because it's a ready-made outfit. A jacket that works with summery dresses is important, so you can wear it in the office and take it off for after-work drinks. We've got an Iris & Ink tailored cotton twill blazer." Your summer sandals may need an update because "this year's version is less embellished, and has a little blocky heel, instead of being flat."

In a holiday suitcase, Phair packs plenty of bikinis. "I take about five, which seems a lot, but it's the one time you can do an outfit change during the day, which is fun."

What we like

Alison Loehnis, MD of Net-A-Porter, tells us what you need in your summer wardrobe

What do women want? Alison Loehnis, the woman at the helm of Net-A-Porter, knows the answer straight away. "Newness – that's what drives sales. More than ever, they want the next season now."

With this in mind, smart customers are snapping up Isabel Marant's studded summer boots. "Summer boots are so practical in this climate. And these will feel totally relevant in the fall." (Although married into London life, Loehnis is half French and half American.) Midi skirts are another shrewd buy. "It's nice to show just a bit of tanned leg. And that hemline is a real coming trend." Her fastest sellers right now are Frame Denim jeans. "I have them in white, in a slim boyfriend fit and a black cropped version. They are the perfect midrise fit."

When it comes to her own wardrobe, Loehnis says, "I'm a jacket person. I'm a fan of a classic, very slightly shrunken blazer: it pulls together so many outfits. Biker jackets aren't going anywhere, either. And this season bombers are huge."

Working in the well-dressed Net-A-Porter offices, it is not surprising that Loehnis wears a heel "pretty much every day – anywhere from a 70[mm] to a 100[mm]." The Net-A-Porter team now numbers 2,000, so for days spent crisscrossing the 66,000 sq ft of offices, Gianvito Rossi pumps are a favourite.

For the summer holidays, she'll trade for Miu Miu parrot sandals. "And Mara Hoffman bikinis, which are amazing; and a Chloé white cotton macramé dress. Oh, and the Oscar de la Renta kaftans are sublime."

What we like

Emma Fox, womenswear buying director of Asos, selects her must-have buys for summer

Take a good look at the jeans Emma Fox is wearing. What you see before you is the shape of things to come: the boyfriend jean. "The skinny jean is still the best performer, but our Asos boyfriend style, the Brady, is doing really well. Especially the ripped version," says Fox.

Much as she loves fashion, it isn't the catwalk that motivates the Asos customer as much as the invites on her mantelpiece (or, more likely these days, in her inbox). "Our woman is very occasion-led, and that means dresses. We have a range of vintage-inspired lace dresses that are doing phenomenally well." Once a beach holiday is booked, that means more dresses and a bikini or two. "We're having our best season ever on swimwear, and it's all about the mix-and-match bikini."

The arrival of festival season also brings its own looks. "This year, dungarees are looking like the major festival trend. Both traditional denim dungarees and pinafore-style dresses, which girls are buying with crop tops. And jumpsuits – printed this year – and lots of crochet."

Summer usually means colour, but in 2013 the minimalist movement has taken hold at Asos: "Clean white separates and all-white dresses are doing better than we would have expected."

Fox also sees the influence of minimalism in the bestselling summer sandals. "The gladiator sandal isn't selling like it was last summer. The sandals that are doing really well are the simple two-part styles, either flat or with a heel."

What we like