Hall of Dreams

'Brookbrown and flag iris, plantain and marsh marigolds rioted on the banks and kingfishers swooped and darted about, their shadows racing over the brown trout', reminisces the leader of the Greater London Council during a speech in front of the riverside County Hall at the beginning of Alfred Hitchcock's Frenzy (1972). 'Well, Ladies and Gentlemen, I'm happy to tell you that these ravishing sights will soon be restored to us again in the near future, thanks to the diligent efforts of your government and your local authority. All the water above this point will be clear - clear of industrial effluent, clear of detergents, clear of the waste products of our society with which for so long we have poisoned our rivers and canals. Let us rejoice that pollution will soon be banished from the waters of this river and there will soon be no foreign bodies...' A scream interrupts his speech. The crowd look down into the river. A woman's naked body, strangled with a club tie, floats face down in the dirty water; the politician's attempt to cleanse London is mocked by a history of murder and madness.

Very shortly, London will have a new local authority and, for the first time, an elected mayor on the US model. These institutions have been created to replace the Greater London Council (GLC) abolished by Margaret Thatcher in 1986. The new mayor and assembly will have Norman Foster's technocratic, glass-faced 'headlamp' building, which also overlooks the Thames, as their headquarters. Foster's architecture - like his Bundestag dome in Berlin - emphasises the democratic virtues of transparency. It is a window looking out on the city. Like the London Eye, the giant Ferris wheel next to the old County Hall, the new seat of local government epitomises the way London wants to see itself: open, rational and self-knowing. But this vision is haunted by an architectural ghost. A mile downriver, the corpse of County Hall stands mouldering like a huge wedding cake in Miss Haversham's bridal chamber. And there are some strange things burrowing away beneath its deathly-white facade.

Salvador Dalí loved the outmoded, forgotten corners of cities. He wrote in praise of the accidental surrealism of the Paris Metro and the way its art nouveau entrances, with their writhing bronze tendrils (the quintessence of 'moderne' when they were built) came, years later, to look like gateways to the underworld. He might have liked County Hall. Since it ceased to be a seat of government, this palatial building, looking enviously at the Houses of Parliament over the Thames, has mutated into a place of subterranean, aquatic fantasies, hotels, a football museum, and now, strangest of all, a dodgy art enterprise called the Dalí Universe.

The Dalí estate has never been shy of a commercial opportunity. Curated by Benjamin Levi of the Stratton Foundation, the Dalí Universe promises to sandwich more that 600 Dalí artworks between the London Aquarium and the London Eye. 'Conceived more as a modern, cutting edge museum of the future rather than a stuffy row of dimly-lit paintings', it contains a hodgepodge of Dalí's late, grandiose sculptures (such as a giant dripping watch), jewellery and furniture. It promises to be tacky fun, like the Dalí museum in Figueres. And it does contain one sensational exhibit - his original painting for the dream sequence in Hitchcock's Spellbound (1941).

The rotting architectural carcass of County Hall is more than a blank spot in the architecture of contemporary London. It is a disturbing throwback, a haunted space. Just think of the ghosts that walk here: Hitchcock; the council employees who died for their country and whose memorial in the building was recently 'insulted', according to British tabloids, by the Japanese Shirayama consortium which actually owns County Hall; radical politicians, such as a younger Ken Livingstone, ex-leader of the GLC in the 80s and independent mayoral candidate in the recent elections, who slashed the price of public transport and, in defiance of the Conservative government over the river, hung a banner across the facade stating the latest unemployment figures.

County Hall, completed in 1933, is full of oddly mixed Gothic and neo-Classical pretensions, explicitly putting London's government on a par with the national one. The clumsy architecture of the building, with its multiple chimneys and grand galleries, makes its current emptiness all the more strange. So much redundant space to fill. In their recent installation Parliament (1999), Jane and Louise Wilson explored the spaces concealed in Pugin's even grander and madder Houses of Parliament; an excavation of the architecture of power has been carried out by time alone at County Hall, and time has a way of uncovering the truly surreal.

Livingstone recently visited the hotel's restaurant and gave it a good review in a newspaper. In the basement of the building, you can find the animal that Damien Hirst transformed into the symbol of Thatcher's free enterprise Britain, not pickled but well-fed, tended by divers and swimming in deep waters to the delight of visitors to the London Aquarium. Sharks - the largest in any British aquarium - swim where the councillors used to debate. The Dalí Universe that is to join it in the labyrinth of County Hall is an equally potent image of the last 20 years of British history. A time when the post-war settlement was abandoned and the market allowed to rule finds its mirror image in the floppy watches, distended elephants and Mae West lips that now inhabit in the company of dead-eyed sharks.

Blair's Britain would like to forget County Hall. Go up on the Ferris wheel instead, and enjoy the new democratic vista. London has a new local government so everything's all right now. But County Hall is a memorial to what really happened in Britain in the last two decades - something violent and perplexing. The anarchy of late Thatcherite London has its monuments in the visceral, scary images of British art at the beginning of the 90s. Rachel Whiteread's House (1993) and Damien Hirst's The Physical Impossibility of Death in the Mind of Someone Living (1991) are perfect images of a period during which 'society' was being replaced by 'the market'. And so too is County Hall. In a sense it's the greatest public artwork of all - a surrealist monument to a time when everyone had to learn to swim with the sharks.