Philip Hensher: The inspiration of this Utopian vision

The Unesco World Heritage Site programme seems an entirely benevolent one, and a programme run with intelligence and verve. It identifies and publicises places of natural beauty and examples of great works of art, but also moments of civilisation not attached to any particular name or of any obvious or conventional loveliness.

It's of enormous use outside the industrialised world, acting as quite an effective encouragement to a government to rearrange its priorities and protect its cultural patrimony, very occasionally deleting sites, such as an oryx sanctuary in Oman, where they felt that insufficient care was being taken. Within the developed world, it helps people to understand that culture and heritage is not just a question of museums and frescoes, chapels and palaces, important though those are. It has very interestingly chosen to list a huge range of structures and settings, very distinct from what the conventional tourist chooses to visit.

One of the most interesting of proposed sites, on the current list for consideration, has been furthered with a polemical exhibition in Germany which opened last week. The German government has proposed, of all things, six Berlin housing estates for the admiration of the world, and the excellent Bauhaus Archive has mounted an exhibition in support of the idea. Or, of course, you could just take the U-bahn and wander round the estates themselves.

I did that very thing last week, and certainly felt like a pioneering tourist. The estates proposed were built between the first years of the Great War and the end of the Weimar Republic. In style, they travel between an absolutely enchanting little garden suburb in primary colours at Falkenberg, very much like a village designed and built by Willy Wonka, and later estates on a bigger and less playful scale. Once or twice, wandering round with a camera, I felt decidedly conspicuous in places still lived in by the less affluent of Berlin.

All the same, they are gloriously interesting, and wonderfully well preserved, though sometimes rather buried under communal gardens which haven't been attended to in years. Some ideas are very strange, such as the centrepiece of the Britz estate in the form of a narrow horseshoe. Others are lovely and effective, such as the Carl Legien estate, where the street fronts are nearly blank, and the living areas open out on to charming garden courtyards.

In some cases, you have to remind yourself why, in fact, you're looking at these things. Actually, there are rather a lot of massive council housing estates near where I live in south London that look very much like some of these proposed World Heritage Sites. The difficulty lies in a phenomenon that ought to be termed The Problem of Vicenza. That beautiful city, the highlights of which were built by Palladio, was so thoroughly ripped off by subsequent centuries of architects that the original city has a tendency to look completely unremarkable.

So it is with the Berlin housing estates. They are mostly pleasant places, but you would not find them remarkable now, diluted as their style has been by nearly a century of imitation. It takes an effort of will to think back, to perceive the idealistic and passionate spirit of their maker - most of them were built by an architect called Bruno Taut. Taut and his colleagues grew up in cities where the poor lived and died without fresh air, without access to any green outside space, where the houses were haphazard and mostly quite ugly, and invariably badly designed for the way its inhabitants lived. One of Taut's main concerns was to design kitchens which would be used only to cook in, and not to provide an optional extra bedroom, as in most of the Berlin tenements. Their revolution was to supply ordinary people with a sight of greenery, a balcony, functioning bathrooms and kitchens, and to build on a modest human scale. Even the biggest of these estates can be walked round in half an hour or so, and, in the smallest, you could quite conceivably know every one of your neighbours.

Modernism, we like to say these days, is fashionable again, but what we mostly mean by that is aristocratic modernism, Margot Beste-Chetwynde's glass-and-rubber country palace. There's obviously a fascination in the showy end of architecture which tourists are apt to want to visit; Mies van der Rohe's Tugendhat villa in Brno has been listed as a World Heritage Site already. Looking at ways in which we plausibly might live lacks, one admits, a certain romance.

I loved, however, the Berlin housing estates, and you can pluck their Utopian premise from where it hangs, tangibly, in the air. They look exactly - and I mean, exactly - like architects' drawings of proposed mass projects, complete with sunshine, trees in blossom and, of course, that woman with a pushchair. They are as pretty and as hopeful as a drawing in a 1950s Ladybird book, and it's as much as you can do, walking around them, not to adopt the poshly optimistic tones of a Pathé news announcer talking about the Kitchen of the Future.

What is so inspiring about this idea is that it acknowledges something which improved the lives of thousands beyond measure, and which even now are perfectly affordable places to live. We've lost that sense of the improvable future, but it's our fault that we can't adopt the optimism of Taut and his colleagues. And after all, they were, over the long term, right in their optimism.

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