No Naughty Bits, Hampstead Theatre, London

Hampstead Theatre seems to be making a habit of presenting new plays that are fictionalised accounts of real-life events. Hard on the heels of Sarah Helms's semi-autobiographical Loyalty, we now have No Naughty Bits, Steve Thompson's delightful, semi-fantasy version of Monty Python's landmark legal battle with America's mighty ABC network.

The piece is set in December 1975, just after the show had been broadcast coast to coast for the first time. The only trouble was the network had edited out most of the naughty bits, reducing the laughs by a quarter. Michael Palin and Terry Gilliam flew to New York to try to persuade the ABC bigwigs to reinstate the cuts made in upcoming transmissions. The cultural contretemps that follows in Thompson's nimble-witted play raises intriguing questions about the nature of comedy, mutual Anglo-American misunderstanding and the often self-defeating operations of censorship.

Gilliam, whose anarchic wackiness is sharply caught by Sam Alexander, is an American with an Oedipally rebellious grudge against the country that spurned him and a gratitude for the freedom of expression nurtured by English public-service broadcasting. But Palin, beautifully evoked by Harry Hadden-Paton, suffers from chronically pliable niceness and our native diffidence.

No Naughty Bits records his metamorphosis from lamb to lion in the face of the sheer absurdity of struggling to defend the liberating silliness of, say, introducing a bisexual romance plot into a sketch about a British war film to a group of po-faced American execs for whom cuts principally mean ad revenue. The first half of the play has its sluggish longueurs but, after the interval, it achieves lift-off into comic bliss for a while in the courtroom scene presided over by an amiably eccentric judge (hilarious Matthew Marsh).

The piece allows complicating, uncomfortable queries to be voiced (were the Python team not so much champions of freedom as just touchy after the departure of John Cleese?) and it throws up many shrewd insights, as when the plaintiffs' lawyer (impressive Clive Rowe) argues that censorship counter-productively arouses prurience: "The bleep [over the phrase "naughty bits"] is what makes it obscene". Happily, those naughty bits are all reinstated here.

To 15 October (020 7722 9301)