Everywhere Mat Snow looks, he sees people in jeans and North Face jackets. Why are we dressed to depress? It's our duty to be flamboyant in times of recession, he argues – not a nation of black-clad Calvinists

We all know those moments when a vaguely troubling impression that has been floating round in your peripheral vision suddenly focuses into knife-sharp clarity. Such a moment struck me when, on our way to the National Gallery a few weeks ago, my daughter and I found that London's Trafalgar Square had been taken over by a festival to celebrate St Patrick's Day.

As you would expect, the noble quad was, for the duration of that bright spring Sunday, a field of green.

Except it wasn't.

Yes, there was an emerald gleam in the rugby shirts, shamrock badges and those outsize leprechaun hats that mushroom in March. But mostly, central London was a riot of what in every British town and city centre has been the default shade for some years now: North Face slate – the matte black of a plastic mac.

Since that day, I spot the North Face logo badging its dingy urban camouflage everywhere: on, it seems, every third person not uniformed as a police officer or an anarchist in last Saturday's protest against the cuts; even, foregrounding a stream of refugees, on the BBC-TV news reporter at Libya's border. Such is the unregarded ubiquity today of the North Face brand that a BBC representative may unthinkingly grant it free screen time without anybody in the corporation, with its stringent rules on product placement, even noticing.

Hidden in plain sight (and boy, is it plain), rather than the catwalk's size-zero shenanigans and the comedy stylings clothes-horsed by the stallions of GQ, this is the real story of how we choose to present ourselves in public. For the first time in recorded history we can wear anything we like as long as we wear something; yet we the people have retreated into a sartorial sobriety that would earn the approval of a Wee Free minister. When it comes to clothes, we're all Calvinists now.

For people like me, who won't see 50 again, today's townscape carries echoes of the yesteryear that fashion historians try to forget. Far from being a bacchanalia of Mods and Mad Men, Teddy Boys and baby doll Diana Dors, what the fading postwar age of austerity in which I grew up mostly meant was the charcoal-grey worsted suit, white Bri-Nylon shirt and egg-stained necktie of severely repressed character. Ladies wore chintz bordering on municipal flowerbed and were birds of paradise compared with their menfolk – and, during the long, damp, windblown months that stretch from the St Leger Stakes to the Ascot Gold Cup, compared with people of every sex today. Unless they're making an effort, the women of 2011 dress much like their men, give or take an Ugg or two: from the mid-thigh down, the dullest denim indigo; above, the modern utility garment that is the North Face jacket, almost always, by customer demand, in black. Or, to be precise and definitely not to be mistaken for the sumptuous velvety drama of a starless night or the gloss of a raven's wing, light-sucking, attention-deflecting off-black. Given a choice from the North Face "family" of 12 colours, not all of them boring, it seems we're all Henry Fords now: any colour you like as long as it's, you know, blackish.

What does this say about us? On a base level, we think we're too fat, so we slim our silhouettes with the darkest tones we can find (notwithstanding that, thus clad, far from our bodies aspiring to the condition of a temple, they actually resemble the fully lagged hot water tank socked away on the half-landing). But, more deeply recessed in our collective psyche as it responds to the zeitgeist, what our Benedictine-black North Face outerwear says is that like any fugitive from the unwelcome attentions of too much reality, we feel safer hugging the shadows. So we wear the shadows that hug us.

Ah, would that Roland Barthes were here today to speculate on what a self-adopted uniform of jeans and branded windcheater says about the discreet charm of the bourgeoisie – or its hidden anxieties. His insights belonged to boom times, when steak, wine and the Citroë* DS made everyone a king and connoisseur, when the thrill of the new needed urgent decoding to add to its relish.

Today we make do with plainer fare. We beat a retreat and pray for stasis, clinging and conforming for dear life, displaying dissent only behind closed doors and the skulking anonymity of cyberspace avatars. The North Face jacket is the talismanic sign of the times where we feel the need to fade into the background and tone down our style to match today's mood of muscular austerity.

It's a look with its roots and first shoots preceding the recession. Since at least the turn of the century, the North Face look has been soaking eastward like a damp patch into the visual fabric of society from its foggy San Francisco epicentre, where North Face's outdoor-wear first wind-and-waterproofed weekend hikers and sailors sandwiched between the roaring Pacific and soaring Rockies.

Today, of course, the most daunting ascent faced by most outward-bound North Face wearers is a shopping mall's escalator, assuming their apparel is bought in a store and not mouse-clicked from an online catalogue illustrated by healthy wind-burnt families backdropped by enticing peaks of surf and mountain. Colour-matched with just about every laptop that does not bear an Apple logo, the grimly fun-free North Face leisure look is actually a form of casual Friday work wear which looks forward to the weekend, while chromatically restraining itself from any visible joy at the prospect. It emanates from Seattle and Silicon Valley, where Starbucks-glugging Microsoft monkeys, Cisco kids, Facebook friends, Intel drones and the rest hit the great outdoors straight after clocking off on Friday.

Almost Soviet in its Utopian vision of a high-tech working week blending into 48 restorative hours in the pines and on the briny coast, this portrait of the information economy salariat at work and play is the compliment today's desperate insecurity pays to yesterday's dreams of freedom. Solemnly braced by North Face for the rigours of the weekend, we loosen but never lose our chains in wholesome release from screen time and the pension plan.

When I try on this argument with my wife, she is sceptical. If North Face is a popular brand, she says, then that is because the last few winters have been shockers and their garments are stuffed with duck down or some such sovereign remedy for a nipping wind. In short, North Face and its generic ilk represent no more than the best practical solution to a simple physical problem. Rather than symbolic statement of self and society, they are clothes reduced to the simplest need for adequate shelter from the elements. Then she takes a long, scrutinising and sardonic look at how I choose to brave those same elements, cocks an eyebrow and turns on her heel.

"Rotarian" is the epithet with which my wife favours my wardrobe, though I prefer the likeness suggested by a pair of road menders of the better class as I strolled by when they jeered: "Where's your motor car, Mr Toad?"

Having as your style gurus the likes of George Melly and Eddie Waring in his It's A Knockout pomp is not for everybody, but it works for me. Hats, tweeds and brogues keep me just as warm and dry as would a North Face anorak, while checks, stripes, mixed earth tones and peacock hues give the inner man a lift, endowing me with the buoyancy, bounce and bumptiousness without which I would struggle to bubble as a self-employed salesman whose only product is himself.

But in my own way, I believe I offer a dab of colour in a sartorial landscape which these days is almost all blot. In your jeans and North Face cagoule, you look to me like Centre Point on a wet Tuesday in November – an overbearing, ugly architectural import with set-square design and drab externals as demoralisingly ill-suited to our soggy flat light as can be. Contrastingly, people like me may be likened to the Natural History Museum, defying the grim outdoors by rooting ourselves in a native vernacular of materials and decoration which draws from the motley, ruffed and cavalier mainstream of our sartorial culture rather than a handful of self-effacingly clerical episodes in which from time to time we have piously repudiated earthly pleasures and surrendered to the gathering gloom.

If I see myself as something of a national treasure, any pleasure I may derive from such a perception is more than dampened by the overwhelming reality that much of my treasurability lies in rarity value. When the thermometer drops below around 16C, it's gathering gloom that's mainstream.

We may well be knee-deep in a new 30-year cycle. From the end of the war until the mid-1970s, when even trade-union leaders exploded into bushy bugger-handles, bookmaker checks and kipper ties, it was as if the uniformed aftermath of compulsory National Service had knocked the sartorial stuffing out of any male born before 1940. Thereafter, for men and women alike, it was all power shoulders, rotisserie tans, highlights and bling – a rainbow nation of ostentation from rompers up to, and sometimes even beyond, the traditional senior citizen sartorial sunset of dun, faun and taupe. Edward Heath, for example, was as dreary a denizen of No 10 as there has ever been, yet even in the decades of high dudgeon after leaving office when he had very little to recommend him, he is at least fondly remembered for turning up to a formal lunch party in a turquoise-and-orange Miami Dolphins sweatshirt. Very jovial he was, it's reported, demonstrating that even in the hardest cases, what's worn can wear into the wearer, even if only over three courses and coffee.

This new cycle where the work-and-play uniform of the West Coast cyberboom has adapted so fittingly to the universal credit bust may, I fear, be characterised as the Age of Cool. "Cool", of course, no longer denotes anything remotely connected with what's hip but instead its diametric opposite, as in "square", daddio, signifying a corporate take-over of Bohemia, much like what took place in the late 1960s when bow-tie daddies who came to maturity in the Eisenhower era suddenly let it all hang out over their brand-new polo-necks in a bid to get with it.

Today, with the likes of North Face as its ubiquitous manifestation, we're being marketed an ersatz freedom that expresses itself as a uniform of self-repression. Moreover, we're being sold a talisman of technological progress enmeshed with outdoor environmental consciousness that is no less bogus upon a moment's examination. Leaving aside the inconvenient truth that its very fabric owes much of its being to unsustainable fossil resources, the popular off-black default choice turns its wearers into living, breathing, grey-day office-blocks – an environmental eyesore no less drearily offensive to the retina and crushing to the soul than Centre Point. Depressingly for the beholder who refuses to blank out such humdrum visual static, what cannot be claimed in monumental size is more than made up for in ever-proliferating number.

But, you may be asking, is all this no more than the hyperventilating bleat of an overwrought, self-styled aesthete of the street? Have we not far more important things to occupy our minds than what we choose to wear when the sun doesn't shine? Does it really matter?

It matters enough to hold up an ornate mirror to the plain truth. Ask anyone of the wartime and post-war generation their recollections of the era, and sooner rather than later they will talk of the dinginess of those decades, the smog-bound, soul-sapping greyness of an age whose one memorable splash of colour came with the Coronation viewed in cinema newsreels. It was the more widespread colour that came with money – budding at the end of the 1950s, flowering in the 1960s, reaching full ripeness in the 1970s – that brought a smile to faces, brightened lives and made things possible.

Today, money and colour are no longer index-linked – except in our minds steeled for adversity, austerity and self-denial. Now is not the time for exuberance, says every fibre of your inner and outer being; now is exactly the time for exuberance, says mine. If ever there was a moment to take a lesson from Heath en fête, it's now that he's safely out of the way: what's worn can and will wear into the wearer. Dress to depress, and depression will take a grip. But cast off the winter weeds of mourning and life will burst renewed into spring flower.