Although Barrie Keeffe, who has died aged 74, wrote a long list of stage plays that fed into, and off, each other – especially in their themes of disaffected youth, criminality and rock music – his one big film, The Long Good Friday (1980), directed by John Mackenzie, seemed like an absolute one-off, not only in the annals of modern British movie-making, but in his career as a writer, too.

Helen Mirren, already a star, was sensational in it, and Bob Hoskins made his breakthrough as Harry Shand, an East End gangster who dreams of a new city rising in the docklands of London with mafia money. The thriller plot also tapped into the underbelly of IRA terrorist activity at the time in a highly imaginative, and frightening, way.

Around the same time, Keeffe, who specialised in short, sharp stage plays, wrote Sus (1979) for the little Soho Poly theatre near Oxford Circus. It is set on the night of a general election, when a black man is detained on suspicion of murder by two racist police officers; the play, still performed worldwide, contributed to the repeal of the “Sus” law – stopping and searching people taken to be suspicious – and its pertinence has been renewed under the Terrorism Act of 2000.

Sus was filmed in 2010, with Clint Dyer and Rafe Spall, but lost the immediate, explosive impact it had had in the theatre, just as a fringe staging of The Long Good Friday in 1997 failed to recreate the essentially cinematic excitement of the film. Keeffe himself rewrote his plays for other media, most notably Bastard Angel (1980) at the Royal Shakespeare Company, a vivid fable of a female rock star on the slide, with inserts of a Berlin concert, as a 1983 TV series, No Excuses, with the same lead actor, Charlotte Cornwell, as Shelley Maze.

Keeffe once said he wrote plays for people who would not be seen dead in the theatre and in that respect he was an outsider, an authentic working-class Londoner who channelled the transformation of his home city since the second world war into almost everything he wrote: Harry Shand’s vision of a new gleaming docklands was, Keeffe admitted, completely outstripped by what actually happened leading up to the Olympic Games in 2012.

The Queen’s silver jubilee of 1977 was a touchstone for a bawling trio of short plays under the heading Barbarians (other cultural reference points were an FA Cup final at Wembley and the Notting Hill carnival) which were revived, still brilliant and punchy, as recently as 2015. And that same jubilee was marked in the same year by Keeffe’s crackling, hilarious Young Vic rewrite of Thomas Middleton’s great Jacobean city comedy A Mad World, My Masters, superbly directed by William Gaskill and Max Stafford-Clark for Joint Stock.

Born in London, Barrie grew up in Forest Gate, in the east of the city, the son of Edward Keeffe – the family of (then) O’Keeffes had arrived from Cork in the mid-19th century - a telecommunications engineer, and his wife, Constance (nee Marsh).

He attended East Ham grammar school and joined the National Youth theatre in the holidays. The NYT’s director, Michael Croft, was his first theatrical mentor and directed his first play, Only a Game (1973), at the Shaw theatre, with Peter Gilmore as an ageing footballer fearing the prospect of life in the lower divisions or a pub in Billericay.

From school Barrie joined the school of life as a journalist on the Stratford Express (1964-75), an experience that informed all his writing (not least the “crucifixion” scene in The Long Good Friday) and was affectionately evoked in Scribes (1975), the newsroom populated by recognisable “types” – played by Edward Judd, Richard Kane and Lynda Marchal before she, too, became a writer as Lynda La Plante – dealing with printers’ strikes and fading Fleet Street aspirations.

In the explosive one-act play Gotcha (1976), Phil Davis, as an angry schoolboy lumbered with a discouraging end-of-term report, confronts three teachers in his comprehensive while dangling a lit cigarette over the uncapped petrol tank of a motorcycle. The boy was an example of an anonymous child ignored throughout his entire education. Keeffe felt nothing much had changed in this respect 30 years later. Not one of the three teachers knows the boy’s name. As Keeffe said of his own education: “If you weren’t academically exceptional, or a sporting achiever, you were invisible.”

The Soho Poly was London’s first fully housed lunchtime theatre, and its co-founder and director, Verity Bargate, was Keeffe’s second important mentor, and indeed his second wife. At the same time, the RSC came calling for their new plays programme at the Warehouse in Covent Garden (now the Donmar Warehouse), and Bastard Angel was preceded in 1977 by Frozen Assets, a dramatic itemisation of the consequences for a young boy who has killed a prison officer.

Finally, in his third important affiliation, Keeffe moved nearer home as an associate at the Theatre Royal, Stratford East, under Philip Hedley, who directed several of his plays, starting with Chorus Girls (1981), an intriguing but unsuccessful rewrite of Lysistrata with Ray Davies of the Kinks, in which Prince Charles, played by Marc Sinden, on a visit to a job centre, is held hostage by the militant girls after he has fallen through a trap door.

This was followed by Better Times (1985), a celebration of George Lansbury and the Poplar councillors of 1921 who defied the London county council’s command to exact higher taxes in an area already devastated by unemployment and poverty; King of England (1988), a discussion of race relations using the framework of King Lear as a retiring tube train driver who sells up to return home to Trinidad; My Girl (1989), a touching study of married poverty in a Leytonstone rented flat; and Not Fade Away (1990), a musical version of an earlier TV play, Waterloo Sunset (1979), with Miriam Karlin sticking up for the elderly people in a home where she has been abandoned.

There were more plays and rewrites, but the Stratford East period completed 15 years of solid achievement at the top of his game. Keeffe acted as a UN ambassador in 1995, tutored at the City University in London (2002-05) and was installed as an honorary DLitt at Warwick University (2010). He listed his recreation in Who’s Who as origami.

Despite being in poor health for some time he never stopped writing. He was married four times: to Dee Truman, a social worker, from 1969 until they divorced 10 years later; to Verity in 1981, the year of her death; to Julia Lindsay, a pop music agent, from 1983 until their divorce in 1993; and in 2012 to Jacky Stoller, a TV and film producer.

He is survived by Jacky, whom he first met around the time of The Long Good Friday; by a younger sister, Sue; and by two stepsons, Sam and Tom, Verity’s children for whom he acted as guardian after her death.

• Barrie Colin Keeffe, playwright and screenwriter, born 31 October 1945; died 10 December 2019

• This article was amended on 12 December 2019. A reference to East Ham grammar school being located in Barking was deleted.