In his novel The Moviegoer, Walker Percy writes about how seeing your everyday surroundings up on a cinema screen somehow authenticates them, conferring a reality they never had before. This is partly what the Black Audio Film Collective's work achieves, for London is the Twilight City now. As in Handsworth Songs and Testament, the BAFC adopts an evocative, poetic free form, comprised of powerful documentary and archival footage, narrative devices, and symbolic imagery. Liberating documentary from its didactic conventions, they synthesise the emotional and the political; the effect is urgent and memorable. 'Sacrifice a piece of the past for the whole of the future': the slogan reverberates through the film like a bell, a nightmarish Orwellian alarm and an elegiac knell. Other voices speak of other Londons: remembered, imagined, dreaded... cities of the mind. Immigrant experience, Section 28, architecture, Big Bang, the Docklands development, down-and-outs - there is too much here for the 52-minute running time, but Trevor Mathison's cacophonous score pulls it together in a cinematic stream of consciousness.