The Mentalists, National Theatre, Lyttelton Loft, London

Male bonding for beginners

Since Sarah Kane's Blasted, it's been impossible to view with equanimity any set that attempts to evoke an anonymous English hotel room. You keep half-expecting Bosnia to burst in and add anal rape, eye-gouging and eating dead babies to the establishment's leisure activities. So I tensed at the sight of soulless en suite mock-up currently on the stage in the Lyttelton Loft. But though at the end of the piece a sledgehammer smashed through the veneer-and-chipboard door, it's a somewhat gentler form of lunacy that descends beforehand on the three-star Finsbury Park accommodation that's the setting for Richard Bean's attractive new comedy, The Mentalists.

Two men in their mid-fifties check into a poky room and start unpacking video equipment. At first, you imagine that there's sexual hanky panky in the offing. Garrulous Morrie (Duncan Preston) is certainly not averse to lensing amateur smut, as a sideline to his barber's business pioneered the penis-in-the-milk-bottle shot.

But the room has, in fact, been hired by his old friend, Ted (Michael Feast), a nervy fleet manager from the Midlands, who wants to be taped delivering a Utopian message to the world. Ted has had a Damascan conversion as a result of reading BF Skinner's Walden Two and wants to set himself up as the enlightened dictator of a community based on behaviourist principles and cleansed of the misguided thinking of the "Mentalists" (Freud and his "junkie mates") who were obsessed with the mind. "Think about it," reasons Ted, "if you're sitting on a bus you don't give a damn what the bloke next to you is thinking about, do you? It's what he's doing with his hands that makes you nervous."

Fortunately, xenophobic, Daily Mail-reading Ted, with his dreams of a hygienic, socially engineered future, is far too hapless a figure to make a dangerous demagogue. He even forgets to bring socks with him, so the tape of his six hours of sharp-suited proselytising is ludicrously undermined by flashes of naked feet of clay. Part of the joke of the piece is how the derided Mentalists would have had a field day with this pair. Their Odd Couple comedy is delivered here with great charm – Duncan Preston's camp and placid Morrie is as easygoing as Michael Feast's Ted is fretfully driven and, beneath the surface, vulnerable.

It emerges that the characters have been allies since their childhood in a Barnardo's home. Mutually supportive, they are also a study of divergent ways of coping with paternal abandonment. If it's made Ted want to turn himself into a benevolent, all-controlling über-father, Morrie has survived by living in a fantasy world where, with his professional hairdresser's soothing touch, he is every woman's dream and where his father appears to have been a versatile Colossus – "the only British boxer to have boxed at every weight" – and unacknowledged as the inventor of the mini skirt because he made the fatal mistake of inviting Mary Quant to one of his parties.

Ted gets his biggest laugh of the evening with his smugly chauvinist declaration that "The Greeks... peaked early", the only talent of their modern descendants the ability to "drive a taxi at 90 miles an hour in fucking flip-flops". The play, too, fails to sustain its initial achievement, lapsing, with the revelations of the second half, into convoluted implausibility. But Sean Holmes's skilful direction helps to disguise the fact that The Mentalists works to two awkwardly distinct timetables as both an on-the-run drama and a leisurely exploration of male friendship. For the beautifully performed double act and the hilariously meandering dialogue, this is a theatrical hotel room worth checking into.

To 20 July (020-7452 3000)