Architecture: When is a Denys Lasdun high-rise horror a pied-a- terre to die for? When it's in St James's

A preview of the retrospective exhibition of the life and work of Sir Denys Lasdun at the Royal Academy of Arts, which opened this week, has convinced me that the best architecture and the very best modern housing are, or can be, one and the same thing. If the "high-rise concrete horror homes" Sir Denys himself designed for a street in Bethnal Green in London's East End in the early Fifties had been built in, say, Hampstead or Knightsbridge, they would have been "luxury, architect-designed pieds- a-terre" for intellectuals and plutocrats.

The two revolutionary "cluster-blocks" Lasdun built to replace blitzed Cockney two-up, two-down terraces are extraordinary buildings. They offer light and spacious flats of a type and character that the young and fashionable would, as they say, "die for" 40 years on. The fact that one of the blocks has been declared unfit to live in and is currently in architectural limbo (will it, won't it be restored?) is no reflection on its design. The Lasdun housing has been shabbily treated for four decades, and not surprisingly has fallen from grace. Many residents, as a video at the exhibition proves, were fond of their capacious and airy flats, and some knew that they could never expect such generosity from a new wave of local authority and housing association brick boxes, characterised by tiny rooms and tinier windows.

A few miles west, in prestigious St James's, stands a block of Lasdun- designed flats overlooking Green Park which has been one of the most sought- after addresses in central London since it was built 30 years ago. The flats are larger than those in Bethnal Green, but not as large as you might expect. And, although their interiors are finished in handsome materials, the architecture of the block is rigorous and unyielding. Here, there is no concession to flanking Georgian, Victorian and Edwardian buildings; and yet the ensemble of Trad and Modern works well together. The views from the St James's flats are quite sublime, and the serenity of their interiors is enviable. Naturally they cost a fortune whenever they come on the market, although that is not very often.

The lesson here is that those with taste and money are just as likely to want a home that, in essence, is very much like a modern council flat in Bethnal Green, as they are to want a chaste Georgian house in Kensington.

What went wrong with Bethnal Green, as with so many of the best modern housing projects, was that these homes were poorly maintained, meanly equipped and often made over to those quite unsuited to them. Recently, I went to visit (with two readers from Deptford) the last of the skyscraping concrete towers on the infamous Pepys estate that has yet to be tarted up in architectural fancy dress in an attempt to pacify residents. Designed in a dramatic and heroic "Brutalist" manner, the tower was a revelation, a truly superb concrete sculpture composed of interlocking duplex flats, each boasting spectacular views on either side of the building, a double- height living room and several changes of level. For the young, hip and well-off, this striking building would make an almost unrivalled city home. For families living on government pay-outs it is nothing short of a disaster (so, too, its re-dressed siblings).

Thirty and 40 years ago, we built cleverly designed and highly original homes for rich and poor alike. But we made damned sure that the modern experience was heaven for those with and hell for those without. In recent years, we have built mean little homes for the poor to replace clever designs that we have not allowed to mature and flourish. Meanwhile, the wealthy and those with a sense of style want the very same homes that the poor have learned to loathe, or have lost. Did I say the very same? Well, not quite. Bethnal Green is not quite St James'sn