THEATRE / It's the way we tell 'em: Joking apart, Terry Johnson's Dead Funny, now in the West End, is a cannily comic look at how we use and define humour. By Paul Taylor

Wittgenstein once observed that he would quite like to have written a philosophical work which consisted entirely of jokes, but that, sadly, this was not possible as he didn't have a sense of humour. Even by his standards, it's an odd remark: first, because you doubt whether anyone who was totally lacking a sense of humour would be able to identify his own deficiencies in that department and, second, because there seems to be a subtle flaw in the logic that equates a sense of humour with the ability to create jokes.

Analogous questions about the nature of humour - the difference, say, between knowing how to make a joke and knowing how to take one, or between spontaneous wit used as a way of confronting your life and comic routines parrotted as a way of turning your back on it - are being aired with particular vigour and penetration now in Dead Funny, the aptly titled Terry Johnson play which opened to well-nigh universal acclaim at the Hampstead Theatre in February and which this evening begins its West End relaunch at the Vaudeville.

As one of the characters remarks, 'Humour's a funny thing,' and Johnson ensures we get the full impact of this by building the play around revealing paradox. The action is set during those few days in the spring of 1992 that saw the death of both Benny Hill and Frankie Howerd. This spate of croaking comics naturally comes as a deep blow to the Dead Funny Society, a group of suburban comedy buffs - equipped with much the same mentality as train-spotters - to whom the play introduces us.

It's a different kind of death rattle, though, to which the drama arrestingly resounds. These few days, it turns out, are also the terminal stages in the marriage of Richard (David Haig), a consultant obstetrician and honorary chairman of the Society, and Ellie (Zoe Wanamaker), a woman at the end of her tether. Almost deranged with desire for a baby, she cannot get her husband to touch her, the physical side of their relationship being reduced now to weekly bouts of sex therapy to which he submits with massive reluctance, physically naked but mentally still fully clothed.

Deprecating her as a humourless killjoy, the comedy aficionados cannot see that she's the only person in their midst who is genuinely, scathingly funny. To people who take refuge in 'the joy of simple laughter', as Richard sanctimoniously puts it, Ellie's brand of wisecrack, which is blisteringly alert to the cocked-up world she finds herself in, just comes across as bad taste. Better to forget about that and dust down some favourite Morecambe and Wise routines.

'There's quite an old theatrical convention of having one extremely witty character,' says Terry Johnson. 'You know, Roseanne territory. It's bloody useful, but I've avoided it before because it seemed a bit easy. Then, when I did use it, she paradoxically became the depressed character and all the others became the ones obsessed by comedy. It was an organic thing; I didn't plan it like that.' Nor, presumably, did he premeditate the ways in which Ellie reverses other bits of received wisdom, such as the notion that a sense of humour is the way to a girl's bed. Ellie can't stand Richard's idea of a joke; it's his body she wants back.

'I think men are more prey than women to kneejerk humorous responses. If you make laughter as a hysterical act,' continues Johnson (who is also the author of Hysteria, the excellent Freud-meets-Dali farce), 'and as the breaking of some kind of mental block, then it will be triggered much more easily in men, who as a sex are more fucked-up, up-tight and defended in their own self-image.'

It's an inexact business, gender- tagging styles of humour. There's an exchange between the two women in the play ('Why is it that men will laugh at absolutely everything except themselves' - 'Same reason that women will laugh at absolutely nothing but men') which strikes you as a bit pat and approximate.

But it's telling that the Dead Funny Society only has one female member, women tending on the whole to develop a more personal and unsystematised sense of what is amusing. Victoria Wood once overheard an old lady emerging from one of her shows: 'I don't find humour funny' was the grim comment. Indeed, there is some humour you need a sense of humour to survive, as Ellie, who was forced to celebrate her third wedding anniversary at a Little and Large gig, eloquently points out.

Ending in a fancy-dress memorial party to Benny Hill which disintegrates into an undignified custard-pie contest as marital infidelities come to light and a gay man emerges from the closet, Dead Funny trains the undeceived eye of an Alan Ayckbourn on to the more primary-coloured, risque territory of a Ray Cooney. But in its cannily comic look at the social, sexual, moral and philosophical implications of how we use and define humour, it falls into a rich tradition that stretches much further back.

Indeed, there are times when it reminds me of Much Ado About Nothing, the greatest play that turns on the link between humour and moral behaviour. The soldiers in that work - locked into their rigid patterns of schoolboyish, defensive banter and quite incapable of adjusting to the fact that Beatrice and Benedick manage to break free from their own brilliant but confining routines of mutual raillery - are clear precursors of the men in Johnson's play. For both groups, 'humour' is a way of clinging to immaturity.

There's also a healthy tradition in English drama of judging a man by the temper and intelligence of his jokes, the heroine of many a Restoration comedy needing to distinguish between the 'true' wit and the 'false' wit, the affected prattling wannabe, like Sparkish in The Country Wife, who is described as 'one of those nauseous offerers at wit'.

Likewise, English literature throngs with folk who pride themselves on the sense of humour they manifestly lack. The classic contemporary instance would be Miss Schofield, the self-professed life- and-soul of the office in Alan Bennett's A Woman of No Importance - her constant refrain, 'We laughed', horribly redolent of the fact that, for others, this was doubtless through gritted teeth. In this and many other respects, she's the direct descendant of the City clerk, Mr Pooter ('How we laughed, except Mr Fosselton'), in The Diary of a Nobody, whose idea of a joke borders on being a crime against humanity.

In a way that makes it a sort of consumers-end counterpart to Trevor Griffiths' Comedians, Dead Funny comes at these issues from the novel point of view of someone who has to live with a comedy buff and his assorted chums. What gives the piece tension as well as bite is the fact that Johnson himself adores these comics (he confessed to me that he is only a playwright because he could never be a stand-up). They emerge unscathed, though you may feel they should be saved from some of their admirers.

Ultimately, the play leaves you with the sense that humour is a way of looking at the world, not reducible to formulas for funniness, and a way of getting things in proportion that can be the reverse of quiescent or resigned. Given this, I perhaps shouldn't have been surprised to learn that Johnson doesn't think of himself as a funny person at all and that his scripts are, at certain stages, peppered with the bracketed reminder '(JOKE)', marking the points where the character will eventually be witty when his creator can finally think of a line.

Certainly, Johnson must have been hard-pressed to see the funny side of things on the night during the original Hampstead run when David Haig was indisposed and the author had to fill the breach himself. Given the tricky nude massage scene and the fact that Johnson, not knowing his lines, had to go on with the book, this must have been no joke. It can only have added to the unreality of the occasion that, on that particular evening, it was a signed performance for the deaf. A comprehensively stiff test for anyone's sense of humour.

Vaudeville Theatre, The Strand, WC2 (071-836 9987)

(Photograph omitted)