Thomas More, Trafalgar Studios, London <!-- none onestar twostar threestar fourstar fivestar -->

In prospect, Thomas More looked as if it might be the most incendiary and compelling of the revivals in the RSC's excellent Gunpowder Season. In practice, this West End transfer of Robert Delamere's production proves an only fitfully provocative experience, if a mountingly irritating one.

With its prefiguring of present-day prejudice against asylum-seekers, the piece is more than an intriguing curiosity. Collaboratively composed, it contains a powerful scene, almost certainly written by Shakespeare, in which More, as Sheriff of London, quells the xenophobic May Day riots of 1517. An adroit blend of conservative cunning and humane tolerance, his speech pacifies the mob.

Lit by flaming torches, the bleakly staged, petrol-reeking episodes of unrest have the right pent-up atmosphere, but their topicality doesn't need underlining with modern dress, which, in fact, diminishes our sense of how ahead of his time More was. Intriguingly, the Protestant state censor seems to have objected less to the play's hero being a Catholic martyr than to its potentially inflammatory depiction of the anti-immigrant mob. The authorities did not want a repeat of 1517 and so can't have been overjoyed at the passages that, today, sound like a Daily Mail editorial.

Embarrassment at these may account for the show's framing device. It is set in a derelict theatre (designed by Simon Higlett), with the actors watching from the seats, when not performing, as if to stress that they are not to be confused with the chauvinistic characters.

The second half of the piece is much weaker. Because of censorship, the play had to be cagey about the reasons for the hero's fall from grace. There's no mention of Henry VIII's divorce when More fatally refuses to sign certain papers, and, of course, the monarch remain an offstage presence.

This doesn't make for taut, vivid drama, nor does the emphasis on "merry More", who, even on the scaffold, jokes about never again having a headache. With his gaunt, haunted face, Nigel Cooke is ill-suited to this side of the character, and his mannered performance makes you feel that it was the martyr's long-suffering family who deserved canonisation.

This play is on at the same time as A Man for All Seasons. Though both are hagiographies, Bolt's play is subtler and richer. Thomas More puts the "chronic" in "chronicle play".

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