Sherman is too wise a bird to play such games. "That could well be," he will allow, "but that's all unconscious. Which is fine. Which is what I would hope. I think writing has a lot to do with being able to unlock your subconscious and then having the craft to channel that. If you are letting your subconscious run free then people are going to respond in equally subconscious ways and then, on a conscious level, read many things into it that may very well be true."
Sherman's career as a playwright took off thrillingly in 1979 with Bent, which is about to be remounted on film under the direction of Sean Mathias. The uncanny is not an element I had noted much in his writing, so I wondered if he always knew that the new play would head in that direction. "Yes, I did," he says. "That was a given. But I think you can see it in some of my other work. Messiah, for instance. As I get older, I become more interested in philosophies that explain existence" - he chuckles - "in a way. But I certainly didn't sit down to write a play about the meaning of life.
"It was a play I wanted to write for 10 years but I just hadn't been able to figure out how to do it. You have ideas, you have feelings, you have suggestions of character, but in theatrical terms they're not concrete and also they're conscious. You have to be able to reach that point where consciously you know what you're doing but at the same time you're unlocking something so that stuff just comes out. Sometimes you set yourself a goal. In this case I started with the conclusion of the play and then went backwards. And so it became a puzzle that I had to work out."
The setting is Cairo in 1942. The German army is daily expected to take the town. In the British Embassy a group of stragglers picks over the chaos, clutching at cultures that are not their own, constructing fantasy versions of themselves and of events.
Cairo is somewhere that has long fascinated Sherman. "It was a place where a wide variety of people were congregating in a fairly desperate situation. Many of those living there were openly eccentric and I suppose that appeals to me. And of course Egypt is a centre of spirituality and mystery. Visiting the temple at Karnak, I realised that that phenomenal civilisation of Ancient Egypt existed longer than our own has.
"Even in the obvious places that tourists go, you have a sense of how fragile our culture is. At the same time you're in modern Egypt which is chaotic and nerve-wracking, and in its own way very beautiful. It's filled with a variety of times and cultures, some of which mesh, some of which don't, many of which are the legends of our culture, completely biblical, so it's both mysterious and recognisable at the same time. I've always found those qualities in modern writing about Egypt, like The Alexandria Quartet [of Lawrence Durrell]. Knowing that it's falsely romantic doesn't keep it from being attractive."
As a play, Some Sunny Day is not without its mysterious side. It has unexpected melodrama, too. It's also rich and teasing and often very funny. "I think as I've grown older I've integrated what's funny and what's serious in a much better way," says Sherman. "They are now usually one and the same thing. When I was writing this, I sat there thinking, `Shouldn't this be funny?' And then, `Well, maybe it is funny,' and then, `Well, Martin, you're funny and so probably that's going to be there.' But I didn't construct it the way you do purposely to be funny, by building laughs. You have to understand that I find the most serious things in life, the saddest things, the most tragic things funny. I don't find any humour in happiness." He chuckles. "Or in things that are easy."
Serious, sad, tragic, difficult and funny, too... this brings us to the exhilarating switchback of a script Sherman wrote for the Nancy Meckler- directed movie Indian Summer which will open next winter. Set in a ballet milieu and centring on an HIV-positive dancer, it has already been aggressively prejudged on these pages. Sherman is unfazed. "It's been absolutely one of the most wonderful experiences of my life," he says. "It's a piece I'm extremely proud of, my first original screenplay, which is something I was afraid of doing for a long time because I heard so many horror stories emanating from America about what happens to movie scripts. On this I had just the opposite experience, but I think that's to do with the fact that there's a respect for writers here that doesn't exist in America. Not to say financial respect," he adds laughing, "but a respect that's important."
Respecting the writer is a daily consideration for the director. Meckler and Roger Michell, who is handling Some Sunny Day, bring out Sherman's warmest response. At the time he was telling me about the play, technical rehearsals were just beginning, so the actors had been at it for four weeks. "It's wonderful having a director who's so absolutely clear about the play," says Sherman. "So clear about what he's doing and so in charge - in a gentle, calm, mature way, but in charge. It's not that I don't have a clear view myself, it's that it's very hard to put it into words. If I could describe it easily in conversation, I wouldn't have written the play.
"Rehearsals teach you a lot. To me a play is meant to be acted on its feet and I find the read-through very deceptive. Things that seem to work very well when read often don't when they're actually on the set and vice versa. But when you have a good director and a good cast, as I certainly do with this, it's deeply rewarding. If you choose to be a playwright as opposed to a novelist or a poet or an essayist, you're deliberately at some level selecting the one form of writing that is both solitary and communal, and if you don't thrive under the communal part you shouldn't be a playwright. You have to love that if you want to write for the theatre." Fortunately for us, while the movies begin to beckon, Sherman goes on wanting to write for the theatre, too.
n `Some Sunny Day' is at the Hampstead Theatre, London NW3 to 18 May. Booking: 0171-722 9301Reuse content