Simon Gray was a prolific and versatile author whose diligence and professionalism gave the lie to an often shambolic appearance and manner. He made an early start as a writer of prose fiction, and for a time had an undistinguished academic career, but he found his true vocation as a writer of plays. He wrote for the stage, for television, for radio and for film. His subjects ranged from historical dramas and allegories to shrewdly satirical studies of modern life and mores. He was at home with all of them.

Almost nothing that he did was less than well written, well thought out, well made. He aimed to entertain, and he usually did. Mostly he observed the conventions, accepted the tried and tested forms. But he turned them always to his own distinctive ends, now undermining them with subtle irony, now bringing them alive with coruscating wit.

He was a shrewd — though not a cruel — observer of human foibles and follies. Few writers have had a keener sense of the oddity or the fragility of what passes for normal life, or a sharper eye and ear for the way people respond when they realise how easily their worlds might fall apart. He was scrupulous but generally sympathetic in his analysis of his characters’ weaknesses — and of his own.

A diarist for much of his life, he produced engaging accounts of the private disasters behind his public success, chronicling the catastrophes surrounding the production of some of his plays. In the last years of his life, in The Smoking Diaries, he recounted with wry honesty the story of a life that always found room for cricket, music, books and films, for talk and friends and lunch, and for cigarettes. The project was an extraordinary and deserved hit, introducing his idiosyncratic talent to a whole new audience.

Born on Hayling Island in 1936, where his father, James, was a GP and later a pathologist, Simon James Holliday Gray was evacuated in 1939 to Montreal, and a house where his grandfather and alcoholic wife were attended upon by a younger aunt.

The children were rarely spoken to, and not encouraged to play; school offered little respite, for they were beaten up, soon learning to do the same unto others, and to find solace in comics and smoking (by the age of 8, Gray was on ten a day).

Savvy and crew-cut, Gray returned to austere England in 1945. Education now took a winding route, from three years at a girls’ school to two at a London prep school; followed by five at Westminster, where he showed some prowess at sports (a lifelong interest, especially cricket, as were films), and fetched up, after a money-making Underground scam, in the juvenile Court. There his speech won approval from the bench and was, evidently, akin to his school performances in which he displayed the “cultivated but not disturbing originality that wins scholarships”.

The sixth form brought a passionate friendship which prompted him to give up games, and homosexuality would recur in his work. Of his adolescent posturing, he said: “If my performances were confidence tricks, then my expensive schooling had given me the confidence to pull them off.”

Financial considerations made his father take the family back to Canada. At Halifax, when studying at Dalhousie, Gray “saw myself as a boulevardier fallen among provincials, and only discovered after I’d left that I’d been seen in my turn as the campus pansy”.

From there, he went to Cambridge, where at Trinity, and later St John’s, he made such friends as Allan Massie, Richard Boston and Tony Gould, but, in that gregarious Footlights era, he later depicted himself as a solitary type, unable to get up in the morning.

For all this angst, which haunts his plays, he read a great deal; in particular the grotesques of Dickens and the mental landscapes of Chekhov (akin to the Fens) would be an abiding influence. He was already writing: a first novel, Colmain (1963), was published by Faber & Faber. It was an unfocused account of life in provincial Canada but it brought him to the attention of a radio producer during a year’s teaching in Vancouver, and the result was a dramatic adaptation which, in due course, would prompt him to recognise his greater skill at dialogue (a much-honed art, sometimes taking him 35 drafts).

The Cambridge of Simple People (1965) and the provincial world of Little Portia (1967), both shot through with allusion, suggest a writer trying to break free of the novel form — a notion galvanised by realising that to write a TV version of a short story brought in far more money, for less effort, than the original work.