Of all the political dramatists who emerged in Britain in the late 1960s, Trevor Griffiths, who has died aged 88, was the most fervent and committed. As a Mancunian Marxist he brought to theatre his love of dialectic. He also believed passionately in “strategic penetration” of the citadels of culture. He succeeded, in that plays such as The Party and Comedians were taken up by the National Theatre; Bill Brand, an 11-part series about the frustrations of parliamentary democracy, was shown on ITV; and his screenplay for Reds, co-authored with Warren Beatty and based on John Reed’s account of the Russian revolution, Ten Days That Shook the World, became an Oscar-winning Hollywood movie.

If there was one theme that informed Griffiths’s work, it was the conflict between reformist pragmatism and revolutionary idealism. It was there in an early work like Occupations, first seen at the Manchester Stables in 1970 and quickly picked up by the RSC for a production starring Patrick Stewart and Ben Kingsley. Set in Turin in 1920 at a time when every engineering factory in northern Italy had been taken over by the workers, the play involves a head-on confrontation between Kabak, a businesslike Comintern representative, and Antonio Gramsci, the Sardinian firebrand advocating shop-floor soviets.

Griffiths’s faith in a drama of argument and debate was seen to even greater effect in The Party, which was staged by the National Theatre at the Old Vic in 1973 and became the occasion for Laurence Olivier’s farewell to the British stage. Olivier played a hard-headed Glaswegian Trotskyite taking part in a dining-room discussion about the need for revolutionary change in Britain and the reasons for its failure. An LSE lecturer and an itinerant dramatist, based on the playwright David Mercer, put their points of view in 20-minute speeches but it was Olivier’s character who came up with the play’s fiercest attack on leftwing intellectuals: “You enjoy biting the hand that feeds you but you’ll never bite it off.”

Even in his most popular stage play, Comedians (1975), Griffiths pursued his big theme: the conflict between reform and revolution. The setting was a night school for budding standups and brilliantly offered multiple perspectives on the theme of comedy. A line-toeing agent from London argued for giving people what they want. The group’s idealistic tutor believed that a true joke had to change the situation. But the wild card was a radical rule-breaker whose act was a mix of Grock-inspired physicality and working-class anger. Inspired by a popular TV show of the time, what is fascinating is how Griffiths’ play anticipated today’s debates about the social purpose of comedy.

Success in theatre did not dent Griffiths’ core belief that television was the ideal form for socialist dramatists and he produced much fine work for the medium. There were single plays such as Absolute Beginners (1974) about Lenin’s break with Trotsky and All Good Men (also 1974) about the compromises faced by a once-impassioned Labour party pioneer. But it was in Bill Brand (1976) that Griffiths was able to explore in well documented detail the difficulties faced by a radical Labour MP when confronted by the messy realities of Westminster.

After co-writing the screenplay for Reds (1981), which consumed a massive amount of time and energy, Griffiths enjoyed a more fitful career but he never lost his passionate belief in drama’s political purpose. In The Gulf Between Us, staged at West Yorkshire Playhouse in 1992, he offered a plea for mutual understanding at a time of Middle East conflict. In Thatcher’s Children, premiered at Bristol Old Vic in 1993, he movingly captured the despoliation of young lives by a doctrinaire leader. And in A New World at Shakespeare’s Globe in 2009 he ingeniously adapted a screenplay, commissioned by Richard Attenborough but never filmed, which traced the impact of the English radical Thomas Paine on the American and French revolutions.

Griffiths was a major political dramatist whose work deserves revival. He was also a good and kindly man. I have a cherished image of the first night of a trilogy of his short plays, To the Mountain, being presented at London’s Theatre Museum in 2006. Tom Stoppard turned up and, although he and Griffiths were polar opposites politically, I have never forgotten the warm bear hug the two men shared. It was a vivid demonstration of the mutual respect of two first-rate writers for each other’s craft.

• Two picture captions in this article was amended on 2 and 3 April 2024. Patrick Stewart and Estelle Kohler are shown in the RSC’s 1971 staging of Occupations, not the 1970 Manchester Stable production. Griffiths is shown with the cast of Oi For England from the 1982 television play, not the touring production.