John Mortimer invariably referred to his father, Clifford, as the major influence on his life. Auberon Waugh, interviewing him, could not steer him from the subject. “Whenever John Mortimer talks about Rumpole, or almost any of his characters, the conversation always returns to his father.”

John inherited Clifford’s retentive memory for literary quotation, his atheism, his terror of boredom; also his asthma and glaucoma. Clifford Mortimer was a skilled and scholarly advocate, who had published Mortimer on Probate at 26. It was true, as John always said, that he had been raised, fed, schooled and nurtured on the proceeds of adultery. Clifford’s divorce cases featured regularly in The Times law reports, when divorces were rare, and evidence was contained in tragic letters between spouses.

With failing eyesight, almost blind in his fifties, Clifford was given to “alarming” rages, and determined (despite John’s ambition to become a writer) to propel his only son into the law. But he adored John: “I think him a genius,” he wrote to his sister, “though Kathleen [his mother] won’t have it so.”

By the time John immortalised Clifford in A Voyage Round My Father (on radio and TV in the 1960s, in the West End in the 1970s, memorably personified by Laurence Olivier in the 1980s televised version, and revived last year by Derek Jacobi), his creation had eclipsed the original, so that John could not recall which of Clifford’s mischievous aphorisms – “All schoolmasters have second-rate minds”, “Immortality would be a terrible bore, like living in some great transcendental hotel with nothing to do in the evenings” – were genuine, and which he had invented.

The nine volumes of Clifford’s diaries contain no such aphorism. His obsession was gardening, and John’s achievements and critical acclaim were mere afterthoughts: “We listened to John’s talk on the radio,” he would write, “and boxed up some rock roses.”

Having fulfilled his father’s aspirations and more – taking silk, achieving a knighthood, creating in Rumpole a barrister based partly on Clifford – John himself began to turn into the old boy reincarnate. In old age, he too requires devoted care. The televised image of Olivier as the blind Clifford in tweed suit and straw hat is replaced by an equally familiar image of the octogenarian John, wheeled through the throng at public events such as the wedding of Charles and Camilla, or the premiere of a new film starring his daughter, Emily.

He became “a man whose private and professional lives float on a tide of affection”, as one profile put it.

Sir John Mortimer, beaming face dominated by owlish glasses, emanates a genial willingness to hail a fellow celebrity or supply a passing gossip columnist with a usable quote.

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