A Man For All Seasons, Theatre Royal Haymarket, London <!-- none onestar twostar threestar fourstar fivestar -->

Martyr with a touch of Blair

If you find the subject of martyrdom "more-ish" (so to speak), then you are in luck, for this week sees the premiere of two West End revivals of plays about Sir Thomas More, the Lord Chancellor who preferred to go to the scaffold rather than compromise his principles and support Henry VIII in his divorce-motivated split with Rome.

The RSC is on the point of opening the London transfer of Thomas More, the collaborative play (in which Shakespeare had a hand) that incurred the displeasure of the censor, partly because of its positive portrait of a Catholic hero. Pipping this revival to the post, though, comes Michael Rudman's shrewdly acted and engrossing production of A Man For All Seasons, the hugely more familiar 1960 Robert Bolt play.

In his recently published diaries, Alan Bennett astutely suggests that writers have tended to be soft on Thomas More. There is something very English, he argues, about the uncomfortable ambiguity of this figure: the tolerant, sceptical author of Utopia was a man who was also quite content to inflict torture on heretics.

Robert Bolt airbrushes out all trace of this dogmatic heresy-hunter. His More is modernised into a champion of the individual conscience. The play's first reviewers rightly drew analogies between the protagonist's principled silence and witnesses who took the Fifth Amendment when appearing before the Un-American Activities Committee.

Gently reasonable, humane, ruefully humorous, witty and understanding, even on his way to the scaffold, Martin Shaw rises most movingly to the challenge of portraying a character whose strategy is largely the passive-aggressive one of postponing martyrdom with sophisticated legal quibbling and obdurate resistance to revealing the grounds of his objections. The actor also gives admirable hints of the impassioned inner life that eventually bursts through the dam of More's tactical reserve in the climactic trial scene. This is a most reluctant hero, and at one point Bolt even has him alluding to Brecht's notion that it's a happy land that does not need heroes.

There is also a quasi-Brechtian commentator, the Common Man (played here with a drolly deadpan subversiveness by Tony Bell) whose time-serving, job-hopping instinct for survival is designed to highlight More's integrity.

Of course, the hero's disinclination to be a hero merely emphasises his natural credentials for this status. His handicap as a dramatic character, however, is that he does not have to overcome any failings (such as spiritual vanity) that might cast doubt on his eligibility for the martyr's crown. He is too comprehensively adorable.

Alison Fiske is excellent as his gruffly long-suffering wife, and Sophie Shaw, who plays his daughter, is touchingly a chip off the intellectual old block in the fine sequence when she tries to outwit him into submission. But you always know that, when the crunch comes, his family will capitulate in loving veneration of the stand that has left them destitute and jeopardised.

There are, however, moments that may disconcert a contemporary audience. Talking about the Apostolic Succession of the Pope, More says that "what matters to me is not whether it is true but that I believe it to be true..." Though in other respects there is a world of difference between the two men, this could be Tony Blair justifying his basis for invading Iraq, and it's a salutary reminder that sincerity is a very slippery virtue indeed.

The revealing contrast, as Kenneth Tynan argued, is with Brecht's Galileo, modern drama's other lone voice against authority. Whereas the astronomer's beliefs could be put to the test, Bolt does not appear to recognise that the intensely personal and subjective notion of truth which he attributes to More is fraught with potential public dangers. A provocative evening, therefore, even if sometimes for reasons that the author might not have approved of.

To 1 April (0870 400 0626)