The writer Brian Clark, who has died aged 89 of an aortic aneurysm, was ahead of his time in tackling the subject of people trying to exercise choice over dying when they have no quality of life left. In his 1972 television play Whose Life Is It Anyway?, Ken Harrison, a sculptor who is left paralysed from the neck down after a car crash, decides against being kept alive by the miracles of modern technology but has to battle medical bureaucracy. “It’s not about death – it’s about dignity and the freedom to choose,” Clark said at the time.

When he originally submitted the script unsolicited to Granada Television in Manchester, its potential was spotted by Walter Mariner, who worked closely with Peter Eckersley, the head of drama, and observed: “The subject was euthanasia, beautifully presented with the arguments for and against finely balanced.”

Mariner had to convince Eckersley that they should produce the play, betting him a bottle of wine that, if it were included among four scripts offered to the director Richard Everitt, he would pick it – and he did.

Everitt regarded it as “outstanding” and set about reducing the 90-minute play to fit an hour-long slot. Ian McShane played Ken and Whose Life Is It Anyway? quickly earned a showing on the American network PBS.

Clark then restored the cut scenes, added more to create a two-hour stage version, and sent the script to a theatre producer. Some eminent actors were invited to play the part but insisted it was unactable because the lead character could not move. Eventually, Tom Conti took it on and the production opened in London’s West End at the Mermaid theatre in 1978, before moving to the Savoy (1978-79), and Whose Life Is It Anyway? won an Olivier award as best new play.

When it transferred to Broadway (Trafalgar theatre, 1979), Conti went with it and won a Tony award as best actor. In a gender-reversal version, Mary Tyler Moore also won a Tony when she starred, her character renamed Claire, at the Royale theatre the following year, and Kim Cattrall played the part, directed by Peter Hall, in a revival at the Harold Pinter theatre in London in 2005. A 1981 film version starred Richard Dreyfuss.

During the 1970s, Clark was a prolific writer for television. Two of his Play for Today productions starred Peter Barkworth in a continuation of the middle-class management roles he had established in The Power Game the previous decade. As Richard Elkinson, he was seen in The Saturday Party (1975), playing a stockbroker who is made redundant, before its sequel, The Country Party (1977), featured him running a restaurant and having his birthday celebrations gatecrashed by both his estranged wife and pregnant girlfriend.

Clark and Barkworth then teamed up with Barry Davis and Mark Shivas, who respectively directed and produced those two plays, and formed a production company, Astramead, to pitch screen and stage ideas. When Barkworth said it had been his long-held ambition to play a bank manager in a TV series, Clark – and a BBC executive – had doubts about how exciting the premise was, but Telford’s Change (1979) was given the go-ahead.

The writer did his research by visiting branches of the Midland Bank and attending their social events. “I have to say, I did find an awful lot of the local bank managers pretty boring,” he said. So he made it the story of a hotshot international banker, Mark Telford, who escapes the rat race by becoming a provincial bank manager in Dover. His scripts traced the effects this has on his wife, Sylvia (played by Hannah Gordon), who stays in London to pursue a showbiz career, and up to 11 million viewers watched.

Brian was born in Bournemouth, to Selina (nee Smith), who worked in a cigarette factory, and Leonard Clark, a blacksmith, and grew up in Bristol, where he attended Merrywood grammar school and fell in love with the stage at the Theatre Royal.

Following a job in a printers’ warehouse and national service with the Royal Signals in the Middle East, he taught English in schools in London and Cumbria. He trained at Central School of Speech and Drama in London (1954-55), but then realised his true ambition was to write. He returned to education by taking a degree in English literature at Nottingham University, then became a staff tutor in drama at Hull University (1968-72).

The success of Whose Life Is It Anyway? on television enabled him to go full-time as a writer. He had three further West End stage successes: Can You Hear Me at the Back? (Piccadilly theatre, 1979-80), with Barkworth in a play about the world of architects and town planners; Kipling (Mermaid theatre, 1984), a one-man show based on the writer’s works and originally commissioned by Channel 4, with Alec McCowen starring in the TV, London and Broadway productions; and The Petition (1986), a two-hander about a retired British army couple (John Mills and Rosemary Harris) whose marriage reaches crisis point, directed by Hall in London and New York.

On television, Barkworth starred when Clark wrote Late Starter (1985), a series about a retired university professor starting life again when his wife walks out, leaving him penniless. Astramead also produced The Price (1985), written by Peter Ransley, with Barkworth as a man who receives a ransom demand when his wife and stepdaughter are kidnapped by the IRA.

Alongside his own writing, Clark ran Amber Lane Press, which published play texts such as Mary O’Malley’s Once a Catholic and Martin Sherman’s Bent. He also taught screenwriting at Surrey Institute of Art and Design Film School (1999-2012).

His first three marriages ended in divorce. He is survived by his fourth wife, the writer and psychotherapist Cherry Potter, whom he married in 1990.

Stephen, the son of his second marriage, died in 2016.

• Brian Robert Clark, writer, born 3 June 1932; died 16 November 2021