In Alan Ayckbourn's nightmares he is psychoanalysed and straightened out. "Then I wouldn't have anything to write about," he says. There is little danger of that. As he embarks on his 77th play, the life and family from which he draws his dark material remains a disturbingly rich source of inspiration.
When Ayckbourn's mother, Irene Worley, died in 1999, aged 93, the playwright wrote, in an address for her funeral: "She gave me far more complexes, hang-ups, phobias, prejudices, inspirations and self-insights than any writer has a right to expect from a parent."
He describes her as "eccentric to say the least", though he was unaware of it through childhood. "Presumably you think all mothers are like that. Then, you find, mine was barking mad. I mean, completely extraordinary, erratic. The time I became of aware of her, she was going through quite an ugly separation with my father, and was absolutely livid that, after 35 affairs, he'd suddenly gone off with a 'sticker'. She was smashing plates and saying: 'All men are bastards!' Of course, I was only seven – I didn't realise I was going to grow up and be a man... I've used her quite a lot too, but only in eccentric, fringe characters."
His parents split up when he was a child, but he visited his father, Horace Ayckbourn, a former deputy leader of the London Symphony Orchestra, in Norfolk during school holidays. "He gave up everything for love: sold his Stradivarius. She, from the second row of violins, also sold hers. And they said: what do we want to do? Let's go and live in Norfolk in a cottage and breed St Bernards. What a weird change! They were surrounded by these massive beasts who dominated their lives." Ayckbourn seems to remember him fondly – at least, a lot more fondly than he does his mother.
He and his father shared an identical sense of humour. "We both got on so well," he says. "He used to drive expensive sports cars far too fast – it was the first time I went over 100 miles an hour." While Ayckbourn inherited this love of cars, he tempered this with caution: his Who's Who entry says his hobby is driving very fast cars, very slowly.
Mid-way through his childhood, Ayckbourn, now 73, acquired a step-brother, Christopher, through his mother's remarriage to a bank manager, Cecil Pye. Ayckbourn and Christopher would spend holidays watching every film that came to the cinema, often 40 a week. "We were close; we just grew apart," he says. "He wanted to be a market gardener and I went into the theatre, and he thought that was the ponciest thing you could do, so we rather fell out about that." He has never seen him since the day he left home.
But while his step-brother may have been vehemently anti-theatre, his daughters were interested in treading the boards, contacting Ayckbourn for advice. His youngest step-niece understudied on two of his shows. "I said, 'Does your dad want to meet up?' And she said, 'No, he doesn't. He thinks you've left it so long you'd better not now, it won't work now'."
It was only when Paul Allen was researching his biography of Ayckbourn, Grinning at the Edge, that the playwright found out he had another brother, this time related to him by blood. "I thought, blimey, the last thing I need at my age is a brother," he says. "He's a half-brother, admittedly, but my father was married before. There's all sorts of things my mother never told me about – she was a nutter." It was only through his stepfather that he learnt, as an adult, that his birth father and mother were never married. "She never mentioned I was illegitimate. I thought, this is rather fine, it's rather romantic really."
Some experiences have had a lasting impact, such as being sent to boarding school aged seven. "My mother obviously wanted to get rid of me, because the school was only down the road. It's only 40 years later one thinks, 'Hang on, why was I sent there at seven? Why did I cry every night when I went to sleep?' "
But he remains pragmatic about a past that he considers – with a writer's detachment – absurd. "Most of the time you feel incredibly grateful that things like that happened, because it gives you a screwed up [frame of reference]," he smiles.
Ayckbourn's own life has been almost conventional in comparison. He has been married twice, yet only officially divorced his first wife, Christine Roland, with whom he split in 1971, when awarded a knighthood in 1997. "If I got knighted, then my first wife, who no longer lived with me, would be Lady A, and Heather would miss out on it." The divorce was carefully timed so both women could technically use the title. "Chris, my first wife, never uses it … but she comes up for Christmas and it's all very amiable because both the boys are hers."
People have long speculated about how autobiographical his plays are. His characters, he says, "all come from me. They're elements of myself. I must have mined myself, I must be empty inside, hack, hack, another piece of character. Some are more direct: the little girl in A Wonderful Day is as close as I got to my childhood. She's just sitting there, listening to adults behaving outrageously. When you write at the speed I do, quite a lot is your subconscious."
I meet Ayckbourn in the garden of his Scarborough home, which has sprawled sideways, as he and his wife, the actress Heather Stoney, have acquired neighbouring properties and knocked through. His elder son lives on the floor above and a flat in the basement is rented out to actors. A rehearsal room adjoins the property, where Ayckbourn can slip into work in the morning still eating his toast, overlooking the sea.
He is notoriously private. "I'm such a control freak the only time I enjoy a party is when I give it." Nevertheless, sitting on his terrace, with the sound of gulls flying overhead, he comes across as amiable, entertaining, a gentleman. He has recovered from a stroke in 2006, which has left him with a slight limp and strong awareness of his own mortality. "I rather naively thought they may have missed me," he laughs. After the stroke, he stepped down as artistic director of the Stephen Joseph Theatre, though continues to debut his plays there. "Concentrate on what you can do – because, as you get on, energy becomes more precious," he says.
A revival of his play Absurd Person Singular, written 40 years ago, is about to return again to Scarborough, where it made its debut. It is in rep alongside his latest work, Surprises, which is set in the future. "There are people alive today who will live to 150," he says. "What are they going to do for 150 years? Don't get married young, I'll tell you that."
He believes his work, as Britain's most performed playwright after Shakespeare, has evolved over the past four decades. "I feel I've moved somewhere, but whether it's upwards, sideways or downwards is for others to judge," he says.
Absurd Person Singular is now "a lot darker" than when first performed; the current version with characters "stumbling in the dark" highlights the clash of shade and light for which Ayckbourn has become so well known. "The company wouldn't have conceived of it being a knockabout farce with no subtext at all. They know me better than that – because I didn't know me better than that [then]."
He has just started writing again. "It was pushing on me, like 'I want to come out'," he says. Awareness of his own mortality was an added incentive: "It isn't due to start rehearsals till May, and will I make it till then? At my most depressed I think, 'Probably not'. [If I do] that gives me a handhold into next year." Once he has started work, it's swift. "I used to write solidly and health-destructively, in five or six days. I take a little longer now, seven or eight days," he says.
Rather than mellowing into world-weariness, Ayckbourn remains full of surprises. He has little by way of uplifting, Werther's Original-style chat about his grandchildren: "I'm not a very good grandparent, I'm very awkward with kids [though] I was very good with my own kids. At the moment, Anna's 13 and Lucas is 10. It's a bit difficult really. Apart from, 'How are things at school', you can't think of much to say. We're very fond of each other, but there's not a great deal of communication."
Similarly, while the nation was buoyed by Olympic spirit, Ayckbourn was oblivious. "I rather gloomily watched a bit of the South African cricket," he says, which England convincingly lost.
Understandably, after so much output, he is worried that his writing could become repetitive. "I need the challenge of the new idea: the one person I'm terrified of is myself because there's a limited number of characters you can write, and a limited amount of dialogue you can write, without absolutely becoming incessantly repetitive. The only way forward is a new idea."
His parents' Larkin-esque messing up of his early life has provided a long-lasting seam. There is little chance of his suddenly being "straightened out". His ambition, he says now, is simply to "stay alive, and keep writing, from play to play".
1939 Born in Hampstead, to short-story writer Irene Worley and deputy leader of the LSO, Horace Ayckbourn.
1956 Starts working at Scarborough Library Theatre. Meets artistic director Stephen Joseph.
1957 Marries Christine Roland, a member of the company. Two sons, Steven and Philip.
1958 Ayckbourn's first professional script, The Square Cat, is commissioned in Scarborough.
1962 Moves to Stoke-on-Trent to set up the Victoria Theatre, now the New Vic.
1965 Relatively Speaking, originally titled "Meet My Father", plays the West End and Scarborough. Congratulatory telegram from Noël Coward.
1971 Starts living with actress Heather Stoney.
1972 Writes Absurd Person Singular. Made artistic director of the Stephen Joseph Theatre, after Joseph dies.
1973 Wins Evening Standard Award for Best Comedy, for Absurd Person Singular.
1973-79 Succession of plays about middle-class marriage.
1980s Experiments with form, including Intimate Exchanges, which has 16 endings.
1985 Laurence Olivier Award for Best Comedy, for A Chorus of Disapproval
1987 Awarded a CBE.
1997 Divorces Roland; marries Stoney. Knighted.
2009 Olivier Special Award.
2012 Absurd Person Singular returns to Scarborough.