As he tells it, beneath the imposing dome of his balding pate, Sir Alan Ayckbourn's head is a strange, dimly lit creative cavern. "When you dream up a play," he says, "it starts to come slowly, like water dripping in a cave. The thing grows like that, drip by drip, on its own. After a while, you go in there and bring one out. Occasionally it'll disappear on you, but you notice another one. There's usually two or three in there at a time."
To date, there have in fact been 72, excavated, written up, astonishingly, in just a week or two, and directed by Ayckbourn at his spiritual home, the Stephen Joseph Theatre in Scarborough, where he first arrived as a stage manager and aspiring actor in 1957. With two more plays than he currently has years, Ayckbourn is, by a thoroughly improbable margin, the most prolific professional playwright in England. More than half of his plays have transferred to London's West End, which also makes him the most successful of his generation or, according to some, of any generation, including Shakespeare in his own lifetime.
His vast, gleaming town house, actually three town houses knocked into one, reflects his trade. His grandchildren's playroom has been converted into a rehearsal space. A self-contained flat below stairs is routinely rented out to company members. But it's not the walls of bookshelves, overflowing from ceiling to polished oak floor – the only untidy corner of an otherwise supremely well-oiled house – that strike you first; it's the enormous, perfectly round table. "We had it made so we could fit a full cast round it at dinner," Ayckbourn says of this neat reflection of both his dedication to theatre in the round and his long-cherished ensemble philosophy.
Sitting in his customary armchair, overlooking the antiquely English Scarborough bay – with its £2 donkey rides, its mêlée of bucket-and-spade and fish-and-chip shops, a beleaguered bingo MC calling out lucky numbers through a crackling loudspeaker, Ayckbourn is in reflective humour. Due to a stroke he suffered two years ago, the coming season will be his last as artistic director of the theatre he inherited nearly 40 years ago.
"When one does interviews like this," he says, "you tend to make it sound as though everything you've done was a thoroughly brilliant decision." The truth, he says, is that he first went into the theatre primarily as a way of meeting girls. He relocated to Scarborough from his native Hampstead because he'd heard there was a job going, and wrote his first play at the behest of his mentor, the theatrical pioneer Stephen Joseph, because they needed cash from the Arts Council in 1959. "They gave us £300, more than I'd ever seen in one place before," Ayckbourn recalls. "I thought, this is money for old rope." But he had the public entranced. By 1975, the "Molière of the middle classes" had five plays running simultaneously in the West End.
Yet the parochialism of his subject matter, the touch of old-fashioned farce about his plays, so beloved by his public, has increasingly exiled him from the adulation of the cognoscenti. In 1986, Sir Peter Hall invited him to form his own company at the National Theatre, hailing him as one of the most perceptive playwrights of the Thatcher era. Hall's successor, Richard Eyre, was less welcoming, commissioning only children's Christmas shows. The incumbent, Nicholas Hytner, has yet to issue an invitation at all.
He'll tell you that he's now immune to criticism, having had too much and then too little recognition. "The Norman Conquests", his 1973 trilogy (Table Manners, Living Together and Round and Round the Garden) depicting the same series of sexually charged misadventures from three different settings in a suburban house, which Kevin Spacey is to revive at the Old Vic next month, "everybody went completely bananas about. 'The best trilogy since Aeschylus'? I mean, come on." But when pushed, he betrays a hint of pique at the turn of fortune and fashion's wheel – does he feel underappreciated in the ranks of the knighted playwrights Stoppard, Pinter and Hare? "I was the first one to get it," he sniffs, "so I suppose somebody loved me. I've become increasingly isolated up here. Deliberately so."
Ayckbourn maintains that he wrote the kind of play he wanted to see, characterised by cunning structural ingenuity, a flagrant theatricality and a keen comic eye on the rotten state of Middle England and its marriages. They are peopled by thwarted, trapped women and bedevilled by a slew of malfunctioning household objects. Woman in Mind, which he's currently reviving with the acclaimed stage actress Janie Dee for his final season, is typical Ayckbourn fare. In it, Dee's character, Susan, knocks herself out on a garden rake and the play, seen entirely through her eyes, charts her retreat from her drab, suburban reality into the company of a champagne-swigging, tennis-playing ' family that she hallucinates. "It's like opening an old scrapbook," Ayckbourn says of revisiting his 1985 hit. "I no longer know the man who wrote it, so I'm reliant on the actors' point of view. With the new plays you're much more in control."
Control appears to be Ayckbourn's keyword. When asked whether he has any regrets about giving up his first ambition to act, he replies, "No, no. As a director, at least you're in control of the thing." It's difficult to imagine him graciously relinquishing the reins of his artistic directorship to Chris Monks in January. "We've already had a chat," he says, "and Chris isn't some young Turk, chasing change. He's not going to come along saying – 'Right, now we're going to do "devised theatre" in plastic bags. Enough of that middle-class crap.'"
His unrivalled love of structure, too, seems closely wedded to his need for control. Intimate Exchanges, which opened in 1982, contains 16 possible plot variations, based on seemingly inconsequential decisions made by the characters; the mind-boggling House & Garden (1999) saw the same ensemble of actors perform two plays simultaneously, every exit from one stage prefiguring an entrance to the other. "Perhaps I am overly aware of how important structure is to a play," he says. "That's why I hate so much devised theatre. So much of it is just so badly structured."
He imposed a moratorium on his work appearing in the West End when his grip over his material began to weaken. London producers refused to stage all three plays of his "Damsels in Distress" trilogy in sequence in 2002. Ayckbourn withdrew the rights, and loudly decried the death of the straight play and the celebrity-riddled decay of the West End in general. "Musicals, musicals, musicals," he says, or plays stuffed with "film actors who can't project past the third row". He relented last year, when Alan Strachan mounted a stellar production of his 1972 classic Absurd Person Singular, saying, "They're welcome to the revivals." Any new shows, on the other hand, he will still only consider staging himself in Scarborough.
As such, his stroke, the effects of which linger in a stiffness in his left side and the occasional catch in his plummy, declarative voice, must have been devastating. "I went to the osteopath, I thought, a healthy man, and just couldn't get up again. [Ayckbourn suffered his stroke mid-appointment.] The first couple of weeks, lying there in the hospital, taking stock of my situation, I came round with the thought, 'My God. I'm playless.' I cannot imagine living without a play in me. Slowly, though, they started to arrive, and everything else, mobility and so on, came back quite quickly.
"But I thought the writing would be easier to get back to than the directing and in fact the opposite has been the case. I've found I'm like a plant in water when I'm out of a rehearsal room. I wilt. I start thinking I'm near death. I use the energy of a cast to swing round the sun, like a rocket uses gravity. The writing took longer and was much more difficult, oddly. You're on your own. I've spent as much time as possible since the stroke in a rehearsal room. Undoubtedly, the theatre is a family, and the rehearsal room is my real home. I'm happiest when I'm there."
Despite such statements, and what you might glean from his plays, Ayckbourn is in fact very happily married to the former actress Heather Stoney, with whom he's lived for 40 years, and has two sons from his first marriage. Of that relationship, with Christine Roland, Ayckbourn says: "Coming from public school, you never even saw a girl. I was so desperate to get married I proposed to anybody. I broke off one engagement [his second], and found myself in the pub the next night proposing to someone else. The ring wasn't even cold from the other finger. How could anyone allow an 18-year-old to endow their life away to someone, however nice? We just became completely different people. It's extraordinary. I get quite angry, thinking about it now." The couple separated seven years later, though they didn't divorce for another 30 years, when he married Stoney.
But Ayckbourn explains that his artistic voice was fully formed by the time he was 16. At which point, he already had a rich seam of pained class aspirations, thwarted ambitions and maladjusted marriages to mine. His father, the first violinist of the London Symphony Orchestra, left his mother when he was six, for the second violinist. His magazine journalist mother, Irene, who by all accounts nursed an unrepentant love of tall tales, booze and cigarettes, and who had no other children, married the local bank manager two years later, a deeply dysfunctional relationship that Ayckbourn eventually helped her escape. "After my mother left my stepfather, he wrote to me saying, incidentally, your mother was technically a bigamist."
Ayckbourn chuckles, recalling this discovery. "She was married to a man before she met my father, and didn't divorce him until 1948. I met him, once, when I was young. My mother and I were going down the Aldwych on a bus and this bloke in a beret came up and said 'Hello, 'Rene.' It was smiles all round. I said – who was that? She said, 'Oh, he was a writer, I was trying to write and he had this flat. So we got married.' The day after the wedding he didn't get up, and she had to go to work. After a few weeks she thought 'Bugger this' and left. These things come out of the woodwork, but I was never quite sure, because she was very eccentric, my mother, and a dreadful liar, whether it was true or not. Trevor was his name.
"I never really knew my father," he continues. "He died when I was 14, so he missed me. The only thing I remember distinctly is sitting up with him once, in Norfolk where he lived. I've never laughed with anybody else as I laughed with him."
Ayckbourn's creative cave, then, echoes with the voices of distant men and oppressed, ebullient women. "I'll carry on writing if I can," he says, with his sideways, secretive smile. "There are one or two ideas floating about in there. And I'll carry on directing, which I must. I'll keep trying. I have to."
'The Norman Conquests' trilogy is at the Old Vic, London SE1 (0870 060 6628, www.oldvictheatre.com), from 11 September to 20 December. 'Woman in Mind' is at the Stephen Joseph Theatre, Scarborough, Yorkshire (01723 370 541, www.sjt.uk.com) from 4 September to 4 October
The bard of the 'burbs: Ayckbourn's greatest hits
Relatively Speaking (1965)
Ayckbourn's seventh play and his first hit is a canny four-hander, exploding middle-class mores and introducing his favourite dramatic setting, a flat and suburban garden.
The Norman Conquests (1973)
A trilogy of plays that can be seen in any order, set in a suburban town house over one weekend. Kevin Spacey's production opens at The Old Vic in September.
Bedroom Farce (1975)
Often hailed his finest, four married couples air their inadequacies, desires and decidedly English inhibitions in four consecutive bedrooms.
Intimate Exchanges (1982)
Four scenes, set in and around a primary school, two performers and 16 possible endings depending on choices made by the characters.
A Chorus of Disapproval (1984)
A playful metadrama in which the unsuspecting Guy is roped in to perform in an am-dram production and becomes entangled with two married women.
House & Garden (1999)
Two plays on adjacent stages. One presents events as seen from the house, the other from the garden, every exit from one stage prefiguring the entrance to the other.