A proper serving of humour

That lure for romantic travelling imaginations, the Trans-Siberian Express, has now become the setting for a classy icicle-sharp comedy which animatedly embraces diamond-smuggling, multiple-personality confusions, a dopey detective, an alluring Russian temptress, a Catholic priest, and, of course, sex.

Writer Rupert Russell has taken some of the oldest ingredients in the history of humour and served them up as an enticingly spicy new dish, demonstrating a flair and wicked confidence that should ensure several green signals along the track to becoming an established comedy writer.

The Hen and Chickens has successfully transformed itself into two adjacent compartments on the Express, so that the audience can see the action in both simultaneously.

Gradually, the eccentric cast begins to assemble itself: Emily Nightingale, a squeaky, upper-class girl, all glamour and innocence; John Smith, a street-wise but sex-starved boy who falls in love with Emily on sight; Charles Dickens, a clergyman as buttoned-up as a high-church cassock; Dwayne Richards, a luminous travel-bore; Nina Prokovitch, an exotic Russian blonde and diamond smuggler; Tracey Elliott, a detective with the sleuthing instincts of a blindfolded sheep, and Dr Henry Sampson, an eyeball-bulgingly mad psychiatrist.

Russell, who writes for the Radio 4 comedy series Dead Ringers, executes his complex plot with mathematical precision, and the result is some glorious comedic equations.

A mad psychiatrist plus two compartments full of false identities is inevitably going to produce some interesting results, as are the parallel uses of the words: "You are gorgeous", which trip off the tongues of besotted men declaring their lust to a blonde smuggler, little knowing that it is also the code-phrase for her to grab their jewels.

Any initial misgivings that Russell has resorted to old comedy stereotypes are banished by a vivacious and highly talented cast. Dave Armand in particular dazzles as the psychiatrist, in an evening with a refreshingly high laughter count.

Until 7 October. Box office: 020 7704 2001.

Moving Parts