Emerging as a dramatist in the late 1950s, Clive Exton was hailed, along with such writers as Alun Owen and Harold Pinter, as one of most distinctive talents writing for television. He even came to be called the television playwright. However, his acute dissections of contemporary life, by turns realistic and satirical, were only part of a long writing career that extended to the cinema and television adaptations of Agatha Christie and P. G. Wodehouse.

Born in London in 1930, Exton, whose real name (and occasional pseudonym) was Brooks, attended Christ’s Hospital School and went to the Central School of Speech and Drama to train for the stage. Although he soon realised he would not make it as an actor, he slogged his way round regional repertory companies while taking jobs in advertising, a dog biscuit factory and a coffee bar.

His aim was stage management, which he achieved with the London producer Donald Albery. Dismayed by the poor quality of the plays he was dealing with, Exton was convinced, as he told his wife, that he could do better and came up with No Fixed Abode, a realistic study of four men in a doss house.

It was intended for the theatre but was eventually taken up by Granada Television, which screened it in 1959 with a cast including Wilfrid Brambell, soon to star in Steptoe and Son. Exton then moved to ABC Television’s Armchair Theatre, which, under the dynamic leadership of Sydney Newman, was in the forefront of encouraging young writers.

There followed further plays in realist vein, including The Silk Purse, a comedy charting family tensions over the daughter’s marriage; Where I Live, about a brother and sister fighting over who should care for their father; and I’ll Have You to Remember, which lays bare an elderly couple’s dark past. In Anger and After (1963), his book on the new British drama, John Russell Taylor declared that “among playwrights at present exclusively wedded to television he stands out as by far the most individual and exciting”.

Exton was also happy to tackle more mainstream assignments, contributing episodes to Knight Errant, the adventures of a modern-day crusader, adapting H. G. Wells’s Kipps and Edgar Wallace’s On the Spot, and collaborating with Francis Durbridge on The World of Tim Frazer (1960), a thriller series.

Having embraced realism so effectively, Exton proceeded to abandon it in favour of satire so savage that even the liberal-minded Newman flinched. In 1962 ABC refused to screen Exton’s play The Big Eat, an attack on the excesses of advertising, and it was picked up by the BBC. Another play for ABC, the black comedy The Trial of Dr Fancy, was recorded but held up for two years. Howard Thomas, ABC’s managing director, considered that its plot of getting people to have their legs amputated and thus line the pockets of a surgeon and a trouser manufacturer would cause too much offence. A later play, The Bone Yard, which featured a mad policeman, also stayed on the shelf for two years.

These setbacks may have prompted Exton to look for other outlets and at this time he started writing for the cinema. He worked with Karel Reisz on Night Must Fall, the 1964 film version of the Emlyn Williams play, with Albert Finney as a psychopathic killer, and four years later Isadora, starring Vanessa Redgrave as Isadora Duncan.

He adapted Joe Orton’s play Entertaining Mr Sloane for the cinema before writing his best (and favourite) screenplay, 10 Rillington Place, an unsensational study of the mass murderer John Christie, played by Richard Attenborough. In very different mode Exton wrote The House in Nightmare Park, a comedy thriller starring Frankie Howerd, and he worked as a script “doctor” on films such as Georgy Girl for which he received no credit.

Exton finally made his stage debut in 1971 with a political satire, Have You Any Washing, Mother Dear?, at the Hampstead Theatre. Other plays followed at irregular intervals.

In television, meanwhile, he started to move away from social realism and barbed satire into more popular fare, with, in the late 1970s, The Crezz, a soap opera set in fashionable West London, and a television version of the radio thriller Dick Barton.

In the 1980s he spent several mainly frustrating years in Hollywood before returning to Britain and television for a new career as an adapter of popular fiction. He helped to bring the crime stories of Ruth Rendell to the screen for the first time, initiating the Inspector Wexford cycle with Wolf to the Slaughter in 1987.

He also began a fruitful partnership with the independent producer Brian Eastman. Their first project was a series of stylish mysteries set in an Art Deco 1930s and featuring Agatha Christie’s Belgian detective, Hercule Poirot, played – definitively, in the opinion of many aficionados – by David Suchet.

Exton adapted many of the short stories and longer novels himself, building up subsidiary characters, including the affable twit Captain Hastings and a plodding Chief Inspector Japp, and injecting humour generally missing from the originals. He also acted as script consultant for the series, which began in 1989, and over almost two decades worked through the entire Poirot canon.

Eastman and Exton turned to another writer who flourished before the war, P. G. Wodehouse. The Jeeves and Wooster stories had been dramatised for television with Ian Carmichael and Dennis Price. This new version, which ran from 1990 to 1993, featured the double act of Hugh Laurie as Wooster and Stephen Fry as his “personal gentleman”. The casting was controversial but triumphantly vindicated.

A third Eastman-Exton series, Rosemary and Thyme (2003), starred Felicity Kendal and Pam Ferris as middle-aged gardening detectives. It was undemanding fare largely dismissed by the critics but it found an audience and showed that in his mid-seventies Exton was as productive as ever.

Exton’s first marriage, to Patricia Ferguson, produced two daughters and was dissolved in 1957. By his second wife, Margaret Reid, he had a son and two daughters.

Clive Exton, playwright and screenwriter, was born on April 11, 1930. He died of cancer on August 16, 2007, aged 77