FEW THINGS ARE more poignant than a vision of the future, because the future has an annoying habit of biting your vision on the bum and proving it wrong. And there are few visions of the future more poignant than that of Robin Hood Gardens in Poplar, East London. You want your stereotypical postwar high-rise gone wrong? This will do nicely. It ticks all the boxes. It glowers. It has stained, ashen concrete. Deck access. Chronic deprivation.

It was made by two architects who thought that they were saving the world. And the pathos of the name! Robin Hood. It’s tailor-made for the Daily Mail, one of many ruins of the welfare state trotted out to “prove” the evil of the old alliance between modern architecture and “socialism”.

It’s homelier today than ever before, thanks to a skin-deep, Carol Smillie-style makeover and nice herbaceous borders. But with the yawning mouth of the Blackwall Tunnel next door looking ready to suck it into Hades and goaded by the fat, glitzy towers of Canary Wharf overhead, Robin Hood still makes a neat “ha, ha, we won” photoshoot for triumphant Thatcherites.

Its architects, the husband-and-wife team of Alison and Peter Smithson, pretty much invented the postwar Britain we’ve been taught to hate: high-rises, walkways, the city of cars, megastructures, nasty, brooding concrete jungles roaming with rottweilers — all, minus the dogs, the Smithsons’ invention.

But don’t blame them entirely. Their heart was in the right place. A new exhibition opening this weekend at the Design Museum hopes, if not to rehabilitate the pair, then at least to remind us how glorious the futures they planned should have been — sexy, fun and, above all, fulfilling.

In 1956, the Smithsons were asked to design the House of the Future — or, at least, of 1981 — for the Ideal Home Exhibition. Their impossibly glamorous vision — showers that also blow-dried you, a hexagonal coffee table that rose from the floor at the touch of a button — wowed postwar, powdered-egg Britain. That was the intention. It was meant to goad the public into looking at the utilitarian reality of the drab welfare state being built around them and to wonder what was going wrong.

The pair burst precociously on to the stage as twentysomethings in the early 1950s with Hunstanton School in Norfolk. Its hardcore “real Modernist” looks — all minimalist Miesian metal beams — were, in part, a critique of the twee, modern-lite style of the Festival of Britain.

But as leaders of the new international architectural avant garde — Team X — they also soon turned their guns on old masters such as Mies van der Rohe and Le Corbusier. Great as they once were, this old generation’s “wipe the slate clean” Modernism, still being peddled in watered-down form in Europe’s new towns and rebuilt cities, was, the Smithsons said, “crushingly banal” and alienating. Rooted in a prewar optimism irrelevant to a 1950s generation shattered by war, the international style was, they insisted, building “yesterday’s dreams, when the rest of us have woken up today”.

In Britain, the Smithsons helped to found the Independent Group, the “youth club” of the new Institute of Contemporary Arts. It starred such angry young hotshots as Eduardo Paolozzi and Richard Hamilton, po-faced with existential angst, or, like such contemporaries as John Osborne and Lindsay Anderson, satirical and pessimistic about the failure of the emerging welfare state to build a modern British culture relevant to the ordinary man or woman in the street.

The Smithsons, though, were optimists. “Only through construction,” they wrote, “can Utopias of the present be realised.” They wanted to use their anger to stimulate this more “real”, less utilitarian modern culture, plugged directly, more democratically, into the consciousness of its people.

The group was crazy about On Growth and Form by the Scottish embryologist D’Arcy Wentworth Thompson, which agued that a common order in nature could be revealed by scientific, rational, positivist study. It was, perhaps, an understandable response to the discontinuity of postwar society — concentration camps, Hiroshima — to hunt for a reassuring structure behind life.

The Smithsons, for instance, grasped new sociological studies of the East End of London, which revealed the tight social structure of the terraced street that had survived the Blitz. They wanted to replicate this, only fused with the futuristic, glamorous modern consumer culture of cars, rock’n’roll and jazz trickling in from America. Just as Richard Hamilton and Eduardo Paolozzi sketched out the base for British Pop Art, so the Smithsons drew the first “pop architecture”, Modernist but populist, the first breath, if you like, of Post-Modernism.

Their influence was apparent when the Sheffield City Architect’s Department built the social housing of the Park Hill estate in Sheffield between 1957 and 1961 on the site of a Victorian slum. But instead of clearing such slums, or shipping whole neighbourhoods to barren new towns, the Smithsons had the radical idea of repairing the slums and building on their qualities.