Pam Gems: Playwright celebrated for her biographical works which explored their subjects’ dark sides

The playwright Pam Gems specialised in biographical plays that celebrated great cultural figures while exposing the dark side of their emotional lives. This wasn't done to upset the apple cart, or for merely sensational reasons, but to explain, or understand, the characters better in their emotional and social contexts.

Thus the stories of Edith Piaf, Queen Christina, Marlene Dietrich, Stanley Spencer and Mrs Pat Campbell were retold from a compassionate feminist point of view but always with one eye on theatrical possibilities. Gems wrote snappy, tough scripts that often benefited from a Brechtian, or minimalist, staging.

Piaf, which she wrote for the Royal Shakespeare Company in 1978, was the best example of this. Jane Lapotaire's title performance in Howard Davies's biting production went on from the small Other Place in Stratford-upon-Avon to the West End and Broadway. The play looked a lot thinner in Peter Hall's more respectful staging with Elaine Paige in 1993, but took off once more three years ago when the dynamic Argentinian actress Elena Roger gave a performance of self-immolating intensity in Jamie Lloyd's fast-paced production, which made a complete virtue of the snapshot scenes.

Gems had the knack of avoidingall the biopic clichés of stilted self-explanatory dialogue. Her writing was always fresh and funny and her method was summed up by the Globe Theatre director Dominic Dromgoole:"She chucks down loosely whatever seems of inherent dramatic merit,then leaves the rest to the star. Intermittently she writes startlingly well, summoning up a period or an inner crisis with a casual phrase, and her plays have a wonderfully big-hearted rough energy, but they're not completely conceived."

In a way, she anticipated our current insatiable appetite for salty biography. And when she anatomised the painter Stanley Spencer in Stanley at the National Theatre in 1996, she impressed the biographer Victoria Glendinning with her dedication to the love drive and remorselessness of her subject. Glendinning was even moved to reflect on how limited and limiting book-biography was as a genre: "How much more exciting," she wrote, "to throw away the documentation and write a play. And how much more difficult, and dangerous."

Pamela Price was born of working- class parents in Bransgore, Hampshire. She wrote plays from an early age but was a latecomer as a professional. She was educated at Brockenhurst Grammar School and Manchester University, where she took a psychology degree and, soon after, married the architect Keith Gems. They had four children and moved to London, where she found a natural home on the burgeoning fringe theatre scene of the early 1970s.

She wrote children's plays, and more overtly feminist dramas for Ed Berman's Almost Free Theatre, and was an inspirational, exemplaryfigure for many of the younger writers and actors at that time. Large, demonstrative, full of energy and good humour, she was a combination of Mother Courage and Peggy Mount, as if the mould of the maternal battle-axe had been broken for a jolly new left-wing model.

Her profile clicked into place with a wonderfully vital comedy, Dusa, Fish, Stas and Vi, directed by Nancy Meckler at the Edinburgh Festival fringe of 1976 before storming Hampstead Theatre and the West End. The four flat-sharing girls of the title – a divorcée, a revolutionary feminist with a strong sex drive, a high class prostitute and a waif-like dope-head – ticked all the right archetype boxes but made the serious comic point that to live alone as a woman was to live as a second-class citizen. There were no proscriptions, but a lot of laughs, and the play seemed absolutely of its time.

This success took her to the RSC, where she followed the reassessment of Queen Christina in 1977 with Piaf and, in 1984, Camille, an emphatically anti-romantic re-write of Alexandre Dumas' consumptive whore Marguerite Gautier, stunningly well played by Frances Barber, given a child (by Gems) whose paternity gave the plot a powerful, melodramatic twist.

Liberty, sexual and political, was the theme of The Danton Affair two years later at the Barbican Theatre, a filleting of the vast Polish chronicle that Andrzej Wajda had used for his stage and screen versions. Robespierre was reinstated as a tortured idealist, reversing the emphasis on Danton's romantic heroism in the Georg Büchner play, but you never felt Gems' heart was in this story.

She was right back on form when Trevor Nunn christened the RSC's new Other Place building in Stratford-upon-Avon in 1991 with The Blue Angel, for which Gems returned to the Heinrich Mann novel Professor Unrat and revealed a much harsher story than in the familiar Josef von Sternberg film with Marlene Dietrich.

Dietrich, like Piaf, was an iconic, legendary figure who fascinated Gems. She had first written a play about her for the Oldham Coliseum in 1984. This became a wonderful vehicle, Marlene, for a glittering, statuesque Siâ* Phillips in the West End in 1997. Marlene was seen preparing for, then giving, a Paris concert in the early 1970s, poised between her own legend and her future waning cabaret career.

Because it was starkly written, some critics thought Marlene too thin. But it had a strong theatrical spine and a great performance. The same was true of the previous year's Stanley at the National Theatre, in which Antony Sher was outstanding as the painter Stanley Spencer, the priapic mystic of Cookham whose visionary genius shone through a private life of sexual muddle with his wife and lesbian mistress. The play was a huge hit and won Gems both the Evening Standard and Olivier best play awards.

Since then, Gems has been more prominent as a translator, providing fine versions of Ibsen's The Lady from the Sea for Trevor Nunn at the Almeida (with the late Natasha Richardson in the lead) and Chekhov's The Cherry Orchard for Jonathan Miller at the Sheffield Crucible in 2007 (with Joanna Lumley as Ranevskaya). This work had begun at Hampstead in 1978, when she provided a witty and idiomatic text of Uncle Vanya for Nigel Hawthorne and Ian Holm.

Her plays about Horatio Nelson and Mrs Pat Campbell were seen, respectively, at the Nuffield, Southampton, and the Theatre Royal, York, in 2005 and 2006. She never stopped writing. The Drill Hall in London gavereadings in 2009 to Winter Love,about the unconsummated passion between Elizabeth of Austria and Ludwig of Bavaria; and to Despatches, a new look, in a post-feminist age, at love and commitment, that brought her full circle to the lost world of Dusa, Fish, Stas and Vi.

She wrote two vaguely autobiographical novels, Mrs Frampton (1986) and Bon Voyage, Mrs Frampton (1988), and she loved gardening in her second home south of Marbella, where the rhododendrons and camellias were renowned. She is survived by Keith and their four children, the eldest of whom, Jonathan Gems, is a playwright and screenwriter.

Iris Pamela Price, playwright: born Bransgore, Hampshire 1 August 1925; married 1949 Keith Gems (two sons, two daughters); died 13 May 2011.