Johnny Byrne- Made on film

With its graphic descriptions of the rock lifestyle of the 1960s, the bestseller, Groupie, written in 1969 by Johnny Byrne and Jenny Fabian, was, briefly, a London media succès de scandale. Yet within a decade, Byrne, who has died aged 72, was well set on the path which, through various twists and turns, sealed his reputation as a reliable source of comforting Sunday evening television. He wrote 29 episodes of All Creatures Great and Small (1977-90) and, from 1992, 23 episodes of Heartbeat.

Byrne started life in a tenement in Dublin's Northside, the eldest of 13 children born to working-class parents. Arriving in Britain in 1956, he cut down Christmas trees in the Lake District, worked on the Liverpool docks and was a guide on the river Thames in Oxford, before teaching English as a foreign language around European capitals.

By the 1960s, he was a tour manager for the American Shel Talmy, who was record producer for the Who and the Kinks - and Byrne's agent. The Irishman began writing poetry and edited several small-circulation magazines. His short stories appeared in the British magazine Science Fantasy (renamed Impulse in 1966). One of his stories was selected by leading Canadian critic Judith Merrill, for her The Best of Science Fiction 1965-1966. Byrne also featured at the Edinburgh festival and at underground happenings, as part of the Poisoned Bellows, alongside poet Spike Hawkins.

Then came Groupie and, in 1970, Byrne's first TV script, for one of the last BBC Wednesday Plays. Made on film, Season of the Witch starred Robert Powell, Paul Nicholas and singer Julie Driscoll as dope-smoking exponents of the counterculture. The early 1970s found Byrne living in a commune, and contributing scripts to Thames TV's children's series Pipkins.

In 1972 came the first of Byrne's two excursions into film, adapting Spike Milligan's book Adolf Hitler - 'My Part in His Downfall'. Jim Dale was an annoyingly chirpy Spike; the genuine article had a cameo, as his own father. The other, To Die For (1994), was once described as a gay version of Randall and Hopkirk (Deceased), and not to be confused with Gus Van Sant's film of the same name.

In his 1960s science fiction, Byrne had dealt with mature themes, but he found that in TV the genre was categorised as juvenilia. He was script editor on the first series of Space 1999 (1975-76), for which he also wrote 11 episodes. Regretting increased American involvement, he observed: "Over-produced series have the smack of death when they finally fetch up on our screens."

From 1981 to 1984, he wrote three Doctor Who stories, including Tom Baker's penultimate performance, and two 1980s ITV series, the daytime drama Miracles Take Longer and the children's series Dodger, Bonzo and the Rest.

Following the initial All Creatures Great and Small, he contributed to the BBC's One By One (1985), a similar series about a trainee vet, then returned, as script consultant, for All Creatures' late 80s revival. Noah's Ark (1997-98), created by him in the Heartbeat mould and starring Anton Rodgers, was less successful. He had a keen interest in Celtic mythology, incorporating themes and character names into sci-fi scripts. He also lectured on former Yugoslavia.

His wife Sandy, whom he married in 1975, and their sons Jasper, Barnaby and Nicholas, survive him.