Pam Gems, one of the country's leading playwrights, sees the world premier of her new play at York this month. She talks to Steve Pratt about motherhood, feminism and writing her first play when she was eight.

AS a girl, Pam Gems would queue up at the stage door of the local theatre to catch a glimpse of the "wonderful creatures" - those actresses who behaved and dressed outrageously on and off the stage. "Now I'm in a lament. Because of film and television, they aren't the divine monsters they used to be," she says.

She names the late Coral Browne and Maggie Smith as falling into that category in recent times, and recognises they're a dying, if not already dead, breed of performer.

Part of the feminist theatre that developed in the 1970s, Gems must be counted among the country's leading playwrights and certainly one of the few women producing consistently successful work. She's best known for the 1978 musical play Piaf, which collected prizes on both sides of the Atlantic. Other work includes plays about Marlene Dietrich, Queen Christina and painter Stanley Spencer, together with adaptations of work by Ibsen, Lorca, Chekhov and Marguerite Duras.

Now 81, arthritis makes her stick-aided progress across the foyer of York Theatre Royal a slow one. Her mind shows no sign of slowing down as her lively conversation proves as she name-drops, in a matter-of-fact not show-off way, and tells stories from the life of a mother-of-four who took up full-time writing in her forties.

She was in York for the read-through of her new play Mrs Pat - as in Mrs Patrick Campbell, the celebrated actress, friend of George Bernard Shaw and the first actress to play Eliza Doolittle in his play, Pygmalion.

Mrs Pat is, without doubt, one of the divine monsters that Gems so admires for a life lived in the full glare of the spotlights on and off the stage. She died in exile and poverty in 1940.

Gems' own story is no less remarkable. She studied psychology at Manchester University, then raised her four children before turning full-time writer as the feminist movement made its mark. The play that put her on the theatrical map - Dusa, Fish, Sas And Vi - followed four women struggling to come to terms with life in the post-pill generation.

Yet she doesn't believe in preaching. "Most of us go to the theatre because we want our imagination fed. We don't want slogans. You do want to be changed. If you don't move people, what's it for?," she says. "There's something else about live performance - when it works, it's incomparable."

She originally wrote Mrs Pat for Trudie Styler, who wanted to go on the road with a play while husband Sting was away touring. That didn't work out and the play was put to one side. Next, a very famous English actress sat on the script for three years until Gems told her, 'I'll be dead before it's done' and asked for it back.

Then Sue Dunderdale, a director with whom she's worked several times, needed a play for a project at RADA. A reading with Celia Imrie took place and afterwards she and Sue decided they'd try and get the play staged.

Mrs Pat found a home at York Theatre Royal, where the play has its world premiere this month on a stage where the real life actress appeared several times in the early 1900s. Now she's being played by Isla Blair.

Born Beatrice Stella Tanner, she made her stage debut in 1888 and made her name five years later starring in Pinero's play, The Second Mrs Tanqueray. Fourteen years after the death of her first husband in 1900, she become the second wife of George Cornwallis-West, a writer previously married to Winston Churchill's mother Jennie Jerome. She continued to use Mrs Patrick Campbell as her stage name. Shaw wrote the role of Eliza Doolittle for her and she played the role - although at 49 was too old for the cockney flower girl - in the original production of Pygmalion.

For Gems, a play about the theatre allows her to explore the art of acting. "I feel there's a lot of misunderstanding about the nature of acting and what it's like to be an actor," she says. "People still think you go about showing off and being a luvvie, but my experience is that off-stage they tend to be shy and tired. Since acting takes so much energy, eight performances a week, you don't have the energy off-stage to mess about."

Writing was always what she wanted to do. She wrote her first play at the age of eight, acting at school and university. She raised four children - including, as she puts it, one who was handicapped and one who was a genius - before writing full-time. She took her child-rearing duties seriously, adding forcefully that she doesn't hold with crches.

On arrival in the capital she "collided with neo-feminism and lunchtime theatre", both of which offered opportunities for a budding playwright. "I hit London at the right time. There were a lot of those tiny theatres and someone would say, 'Phil Davis wants to direct, can you write a play?' It was a learning curve for me and grew from there," she recalls.

After being staged at the Edinburgh Festival, Dusa, Fish, Stas and Vi transferred to Hampstead Theatre in London. Requiring just one set and four actresses made it attractive to a playhouse running out of money at the end of the financial year.

The play was originally called Dead Fish until someone pointed out this gave away the end of the play. So it became Dusa, Fish, Stas and Vi temporarily until she could think of a better title. She never did. Its success took her by surprise. "We had no expectations. It was just extraordinary, it was lovely. We were liked," she says.

The musical play about Edith Piaf gave Gems her biggest hit. She was another strong women - like Dietrich, Queen Christina and now Mrs Pat - who are the object of both fascination and admiration.

Choosing a subject appears to be random, just a case of something catching her eye. Marlene Dietrich, the subject of her 1999 play, was a real heroine, she says. A very brave woman who was never a great actress but was a great beauty who had an incredible career. Gems was reduced to tears when she saw her perform on stage in London.

Her interest in Queen Christina was sparked by her similarity in looks to Greta Garbo, although her story was ripe for dramatisation. "She'd been reared as a man, put on the throne, been told she must marry and breed. That's drama. I fell in love with it," she says, recalling that the opening night was broken up by left-wing feminists protesting that there were men on stage.

Gems was horrified on coming to London to find there was twice as much work for men as women, so she deliberately wrote strong roles for women. The main exception was her 1996 play about painter Stanley Spencer, written after coming across a book about him at a friend's house.

Gems writes all the time because "it's in my nature", she says, adding, "It's hard, playwriting. It's much easier to write prose."

She has ambitions to write a play about the American singer Ethel Mermen. "I adore her. She stands for everything America used to be before they went into the last war and Watergate and everything got corroded."

For the moment, Mrs Pat is occupying her attention. "She was, no doubt, a monster. She was very badly behaved. She chose dreadful plays because she loved money. She wouldn't do Shaw, until Pygmalion, because he didn't make money.

"Shaw wrote to her when she was in Hollywood and said she had to understand that she had to learn to play comedy and make a small amount. He said he wasn't sending her money because she'd lived on air for 20 years. He did offer to pay her bills, but she was offended. Her glory was when she was young she was very beautiful and very talented.

"We all act and all perform. It's part of being human. It interests me very much and Mrs Pat seemed to be the epitome of the popular notion of an actor - beautiful, glamorous, demanding."

l Mrs Pat is at York Theatre Royal, March 13 to April 1. Tickets (01904) 623568.