THEATRE / Double fantasy: Paul Taylor on Looking Through a Glass Onion at the Criterion

You are a big rock / pop star and you've reached that fatal date with premature death. As the assassin starts to level his gun, or the plane tilts, or the toxins in your body launch their ultimate protest, what rushes through your mind? A delirious re-run of all the adulation and sex 'n' drugs you've managed to pack into a short life? Or the ghastly thought that in a decade's time, some run-of-the-mill lookalike may well be fronting a West End show lazily based on your music?

Forever Plaid, now at the Apollo, parodies this formula by summoning to the posthumous spotlight a fictitious, totally unheard-of Sixties close harmony group. Killed before they had even reached their prime by a busful of Catholic schoolgirls bound for the Beatles' debut on the Ed Sullivan show, the boys are now allowed a one- night exeat from Time's mothballs to perform the sort of high-profile show they never got to do in life.

A bit contrived? Well, it makes more arresting sense than the approach taken to John Lennon in Looking Through a Glass Onion, a show in which John Waters poses as the ex- Beatle at the very end of his life and links his (rather good) rendition of Lennon's songs with a monologue through his deeply familiar past. The title image, from the song 'Glass Onion', seems to promise a peeling away of the layers of a crystal ball, but if Lennon essence is conveyed at all here it's more in short, regular squirts.

The show is framed by Lennon's observations on the young 'un approaching him outside the Dakota building: 'He's gorra book, The Catcher in the Rye . . . Funny, he looks more of a Mills & Boon type to me.' Waters does a very good imitation of the sardonic Scouse intonation of such remarks. The trouble with the quirky apologia pro vita sua in between is that it's all given such a palatable glow by the soon-to-be-tragic context. The Lennon here may recall how his attention-seeking bolshiness found an early outlet in the communal masturbation-sessions at Quarry Ban Primary (when it was his turn to call out a sex object, he'd shout 'Frank Sinatra'), but retrospect puts slug-trails of syrup over his spikiness.

The bite is still there in the songs, performed gutsily with an excellent backing group - the numbers written after the Beatles' disbandment standing up surprisingly well for all their sloganising and open-heart auto-surgery. But the contradictions in Lennon, the multi-millionaire who once arrived in a white Rolls Royce to fast on the steps of a church, can't be dramatised in this format. Some are mentioned, which is not the same thing. But, then, the Lennon we're allowed to catch up with here is Yoko's mellow house-husband, staying in to make bread and look after Sean while she went out and acquired property. And for all the skill that has gone into Glass Onion, a Lennon that doesn't leave you in at least two minds is only a fraction of the real thing.