Shaw's "religious pantomime", in Desmond MacCarthy's phrase, is rarely done these days. Yet Steam Industry's performance in this amphitheatre under the shadow of Tower Bridge drew a large, noisy throng - possibly because it is free and possibly because of the campy exuberance of Phil Willmott's production.
In fact, Shaw's 1913 play is slightly subtler than it first looks. The idea of the Greek tailor who draws a thorn from a lion's paw and then finds himself confronting the beast in the Coliseum is not merely a piece of nursery whimsy. Shaw contrasts the humility of the pagan hero with the the shifty hypocrisy and muscular militancy of the Christian martyrs, Spintho and Ferrovius. But, in addition to familiar Shavian reversal, the play also offers a testament to the power of faith - the willingness of the heroine, Lavinia, to sacrifice herself for God is a metaphor for Shaw's belief in socialism and the life force.
The nuances tend to get lost in Willmott's broad, open-air production. Stewart Alexander's Ferrovius is an American Bible-Belt figure leading a bunch of happy-clappy Christians singing "When the Saints Go Marching in." The Coliseum director is a kiss-curled, cigarette-smoking mix of Noël Coward and Charles Hawtrey. And Willmott brings a touch of Kenneth Williams's outraged pomp to his performance as the Roman emperor. Yet none of this can undermine the power of Shaw's prose or his fascination with martyrdom. Even in this jolly show, with its puppet-lion and Coliseum capers, you are reminded that Shaw was a secularist haunted by the idea of spiritual affirmation.
· Until September 5. Details: morelondon.com