THEATRE / Some things your father should know: Neil Bartlett, actor, writer, director, says it's still considered improper for a gay man to impersonate a straight one. Which is where his father, Trevor, comes in. Interview by Paul Taylor

When Neil Bartlett's Night after Night hit Oxford during its extensive pre-London tour, the local 'Daily Information' sheet described the piece as 'a musical of the typical 'boy meets girl' variety'. This was either a conscious tease or seriously misleading, for though the show plunges you into the golden age of post- War musical comedy, it would be more accurately characterised as a musical of the 'boy meets father' variety - a class in which it has the field pretty much to itself.

Bartlett's scrutiny is partly trained on the chorus boys who provided the mobile background in Fifties musicals and on the piquant discrepancies between their own predominantly gay lives and the schmaltzy heterosexual romances to which they contributed their mute athleticism. On stage, a butch cowboy; off stage, a screamer called Mavis.

At the centre of the piece, though, is another, more jolting instance of a gay man impersonating a heterosexual one, for Bartlett takes on a dual identity during the evening, portraying both himself, and his father, Trevor, who is still alive. In the play-within-the-play, we are asked to imagine that it's a rainy spring evening in 1958 and that to celebrate the news that a son is on the way (the son being Neil, the future author, director, translator, founder member of the theatre company Gloria, and artistic director designate of the Lyric, Hammersmith) the father is waiting for his pregnant wife at a West End theatre where they are to see a show.

The most famous expectant father in musicals, hitherto, has been Billy Bigelow from Carousel and the classic song of speculation about forthcoming fatherhood is that character's long 'Soliloquy'. Two of its more swaggering lines are invoked in Night after Night: 'He'd better look a lot like me / The spittin' image of his dad . . .' It's the ironic premise of Bartlett's musical that, though Neil has grown up into a physical replica of Trevor, there the resemblance abruptly ceases. Identical bodies; disparate bodily inclinations. A musical reflection on how the same kind of art can speak to two such different men, Night after Night also looks back to a moment of looking forward as Neil, now a (childless) adult, observes Trevor apprehensively dreaming of their future.

I asked Bartlett over lunch in Oxford whether the show underestimates how far, even in 1958, the orientation of certain theatrical types would have been an open secret. Would it really have come as a shock to people like his dad? 'My father was a PE teacher and a rugby player and he admired the choreography in West Side Story, say, as wonderful athletics. He told me, 'If I'd known at the time they were poofs, I wouldn't have taken your mother to see it.' Some people have said in response to the show, 'Look, there have always been gay people working in theatre and do we really need to talk about it?' Well, yes, we do. The hierarchy of impersonation, of who is allowed to speak, in what guise, is very powerful. It's actually not considered proper for a gay person to impersonate a straight one.'

You can pick holes in this as a generalisation (after all, Tamburlaine is a fairly unambiguous het, but there hasn't been noticeable outrage that Antony Sher is now playing him), at the same time as acknowledging its force in the specific case of a homosexual pretending to be his father. Up at the Edinburgh Festival, where the show was launched, I heard someone claim that its unacknowledged subtext is a gay man's difficulty in fully crediting that his father is straight. Report such responses to the author / star and he looks pleased and intrigued. The piece invites uneasiness at the presumption of the doubling; it also invites you to examine why you feel that way.

To put the confrontation between father and son in the foreground, Bartlett has altered details of family history (the show leads you to believe that Neil is the couple's first-born; in fact, there is an older 'no less loved' sister). He has also made the mother an off-stage presence; it's her lateness in arriving that creates the tension about whether the ending will be happy. 'I mean you can't have a show without a girl, can you?' asks Trevor, a question that seems to reverberate beyond musical comedy convention.

There's even a dream-ballet in which father and son perform a pas de deux which acts out conflicts and readjustments and ends in a loving embrace. When I protest to Bartlett that Trevor isn't sufficiently seen in his own right, but comes across as a vehicle for the working-out of the author's own hang-ups, he argues that the show makes it quite clear that the father 'is being portrayed as a fantasy projection, on some level, of mine. I think the dream-ballet stages a common and very powerful fantasy among gay people. An embrace between two men is prohibited, but even more forbidden than the embrace between lovers is the embrace between the parent and the gay child. Everyone I know approves of lowering the age of consent - for other people's children . . . .'

Bartlett's long dossier of work with Gloria looks, from one angle, extremely varied, ranging from A Vision of Love Revealed in Sleep, in which he appeared stark-naked and depilated as Simeon Solomon, the gay, ostracised 19th-century painter, to A Judgement in Stone, a musical version of a Ruth Rendell thriller.

An uncompromisingly gay sensibility informs everything he does, though, along with a refusal to regard vulgarity and significance as in any way antithetical. This means that when it fails to come off, the result is what one critic described as 'a highbrow dog's breakfast'. There are also recurring preoccupations - a strong urge, for example, to demonstrate that gay culture did not begin in 1969. Reclaiming the homosexual past is as much a feature of Night after Night as it is of Who Was That Man?, Bartlett's personal prose meditation on Oscar Wilde.

Would it be fair to say, I wondered, that his work has got rather stuck in a style of camp defiance? After all, you could argue that the gay world needs more drag and aestheticism about as badly as Imelda Marcos needs more shoes. Bartlett wasn't at all taken with this proposition. 'People say, 'It's time you got over this. It's time you moved on.' And I say, well, into what culture am I supposed to move? Where is this culture in which I'm going to feel at home?'

There is, consequently, something of a paradox about his theatrical work, for if it seems, at times, separatist in message and outlook, it has become increasingly assimilationist in its ambitions and marketing strategies. The tour has played in large venues to mixed audiences and winds up not at the Drill Hall or for six nights at the Riverside, but on the main stage of the Royal Court. 'I will not accept,' Bartlett declares, 'that because I'm gay I should really be in a studio theatre.'

Next year, if its appeal fund reaches its pounds 350,000 target, he takes over at the Lyric, Hammersmith where his powers of across-the-board appeal will certainly be put to the test. He was feeling touchy when I saw him because in an earlier interview, the first question had been, 'Does this mean that the Lyric is going to become a gay theatre?' Ruefully, he contrasts his own position as an 'out' artist with that of other directors, who though not in the closet haven't gone public: 'You're not going to ask if their work is really addressing the human condition, or if it's self-indulgent or camp?' Why not do plays then, in which homosexuality is treated as thoroughly and as unglamorously normal? When you ask that, you realise that Bartlett's work invites the 'unequal scrutiny' it also resents.

Finally, the question I kept having to come back to throughout our meeting. What on earth will Trevor Bartlett think when he sees the show? Neil prevaricated with talk about how well they get on and that he hoped his father would realise that the portrait was written with love and that many of the words came from Trevor in the first place and, no, he won't be going to the first night because the two of them look so alike there'd be no missing him and he doesn't want to subject his father to that kind of attention - 'you can tell that I'm incredibly defensive about this'. So what intrigues him most about Trevor's reaction? 'I want to know what he thinks of himself up on that stage surrounded by all those queens.'

'Night after Night' opens at the Royal Court, London SW1, on Friday (Box office: 071-730 1745)

(Photograph omitted)