Blair on Broadway, Arts Theatre, London

Though Tony Blair's air-guitar administration ought to provoke scathing satire, for the most part criticism of our leaders has been feeble, a mere assertion of dislike and disrespect. The latest example is this musical, whose impoverished-nursery production values and general amateurishness reach depths previously unknown in the West End. The show has dropped the interval it had during a previous run, yet, halfway through, an actor comes on and says, "Welcome back."

The conceit of Blair on Broadway (book and lyrics by Iain Hollingshead, music by Timothy Muller, direction by Jessica Dawes) is that the former prime minister, "the greatest actor of our age", is starring in a musical based on his career. Yet, apart from singers chorusing "Blair on Broadway! Blair on Broadway!" there is no attempt to locate the show in New York, to exploit the adulation Blair receives from Americans merely for being educated and articulate. George Bush appears, but is deferential and naive, dazzled by Blair, a bizarre take on a relationship attacked for being precisely the reverse.

As Blair, Joshua Martin blinks and chatters mechanically, a pallid version of Jon Culshaw's masterly impersonation on Dead Ringers. The writing is so mindless that it's hard to believe the actors are not making it up as they go along. Blair, in a T-shirt that says "I wanna be a rock star", muses that he and Brown are like "Noel and Liam, John Lennon and Paul McCartney, Ant and Dec..." Cherie, holding a barrister's wig and lots of shopping bags, sings, "I'll stand by my man... and if he ever needs a friend, I'll be there to the bitter end." To call this puerile is giving it more credit than it deserves.

The only departure from the posturing and whining is Chris Cambridge's Brown, a type of Frankenstein monster who lurches about, at one point laying into Blair, who bats him away and screeches like a little girl. But this cartoonish crudeness lands no more blows than the script's timid impertinence. With nothing to say, but not feeling that should stop them, the show's creators have a lot in common with its star.

To 31 January (0844 847 1608)