The People Next Door, Theatre Royal, Stratford East, London

A whiff of Afroman's paean to druggie procrastination, "Because I Got High", fills the auditorium and the lights go up on Nigel doing just that. A mixed-race, care in the community case, Nigel insulates himself from the outside world with his heroin, his videos and his X-Box.

In the paranoid, post-9/11 climate of The People Next Door the police come looking for Nigel's Muslim half-brother. "They got a hard-on for Muslims," says Nigel's 15-year-old neighbour, Marco (a beautifully vulnerable Jimmy Akingbola). Until this point Nigel believed jihad to be an X-Box game. He may fantasise about being a gangsta, but at heart he's the nice boy who always pays the elderly Mrs Mac (Colette O'Neill) her money for cleaning the stairs.

Henry Adam's Edinburgh Fringe Festival hit is an audacious comedy about isolation, trust and persecution in the aftermath of the Twin Towers. Paul Albertson's plain clothes copper Phil blasts the play into life with a Sweeney-style - almost decadent - ruthlessness, masking a snake pit of psychoses. He makes Irvine Welsh's DS Bruce Robertson from Filth look like Dixon of Dock Green.

At the passive end of the sociopathic scale, Fraser Ayres's psychologically frangible Nigel is a cacophony of slacker ticks and poses. Jittery even in repose, labouring hard to be street, Adam gives him lines that sound like a scrambled signal from trash culture hell. It's a performance that could easily tip over into cutesy Forrest Gump territory. But director Roxana Silbert keeps the histrionics at bay all round, ensuring that the audience understands it is the world that has gone mad, and not Adam's characters.

Bleakly hilarious as the play is, Adam's triumph is in the script's humanity. The message is one of hope, as Nigel slowly gets drawn into society despite Phil's attempts at preying on his alienation. Some genuine warmth shines through the rubble.

Arthur Miller once said that if he were to start all over again, he would prefer to be a stand-up comic. Indeed the most powerful reaction to the post-9/11 climate - The Crucible to the McCarthy witch-hunts for the 21st Century - is the satirical comic strip In the Shadow of No Towers. Adam's script opens with a quote from this strip, which was published in this newspaper last week. But The People Next Door proves that the theatre is still a vital satirical tool, its greatest strength being its speed. We can watch and laugh and writhe uncomfortably at what takes place on stage then step out of the theatre into the darkness of the real world it satirises.

Waiting for a green light in film or TV, to borrow from Art Spiegelman, risks the chance of a new disaster striking while we're still chipping away at the old one.

To 4 October (020-8534 0310)