C.S. Lewis believed, the cards are stacked against the forces of darkness, for human beings are naturally inclined to goodness, even in its simplest forms of sleeping, eating, playing and making love.

Lewis’ devout Christian belief in the goodness of man shines through in this idiosyncratic play based on his enormously popular epistolary novel, “The Screwtape Letters”.

Yannick Lawry plays Screwtape, a senior demon consumed with overweening pride, styled as an Oxford don. Through the medium of his sidekick Toadpipe, played by the versatile George Zhaohe who writes letters to his novice demon nephew Wormwood, instructing him in the art of tempting and corrupting a good young man.

In this theatrical adaptation we never get to meet Wormwood. Screwtape plays it as straight as a demon can, so Zhao, acting as a kind of cross between amanuensis and Quasimodo, has the lion’s share of the acting as he plays most of the offstage characters.

We are told that the Devil has the best tunes, but that’s not the way Screwtape sees it, lamenting the disadvantages under which he labours. Even death, he complains, is no punishment for Wormwood’s “patient”, because it brings to an end the opportunities to destroy a soul.

Lewis and his adapter McQueen, in analysing the nature of sin and goodness, turn our normal perceptions upside down and inside out, giving the curious sensation of seeing the world in negative.

To be sure Screwtape attempts to engage us, Richard III-like, in his satirical observations on the mediocrity of English society. And in this beautifully staged version set in an almost Faustian professorial study, there are many games to be played.

There is, for instance, the problem how to despatch the letters to Wormwood, as he does with increasing killer sound effects. Even more difficult is receiving the letters, which turn up from the ether, in the props, and even from the rear end of Toadpipe.

The Christian symbolism is if anything more obvious than in Lewis’s “Narnia Chronicles” as we, the audience, view Screwtape’s increasing frustration. Onstage, the relationship between master and servant is front and centre, deteriorating as the play goes on.

Lewis presents us with the likelihood that there are far more than seven deadly sins, even if some, like mixing Christianity with vegetarianism or sending your plate back at a restaurant, appear to be on the mild side.

To my mind, the dialectic often gets in the way of the drama, however, as Screwtape endeavours to navigate the subtle art of corruption through an elaborate offstage scenario.

This allegory of good versus evil played to the enormous enjoyment of a committed audience.