THE last time Not Going Out star Deborah Grant was in York, she was playing a raucous postmistress in gaudy Bet Lynch garb, quoting great chunks of the Bible, in Ruth Rendell's bizarre mystery A Judgement In Stone.

She returns to the Grand Opera House from Monday, in altogether more elegant garb, in another Bill Kenwright-backed tour by the Classic Thriller Theatre Company, Edgar Wallace's murder mystery The Case Of The Frightened Lady, again directed by Roy Marsden.

"This is a very different piece: a whodunit, whereas last year's play was a 'whydunit', where you knew from the start who had done it, but the question was why," says Deborah, recalling last October's visit to York. "People have said they prefer a whodunit, as they like playing at being Poirot or Miss Marple, and we have a wonderful history of crime writers in this country."

Writers such as Richard Horatio Edgar Wallace, who was born into poverty as an illegitimate child in Greenwich, London, in 1875 and died in Beverly Hills, California in 1932 – the year in which The Case Of The Frightened Lady is set – such was the trajectory of a career wherein he wrote 150 detective novels and was "the brains" behind the iconic film King Kong.

Newly adapted for the stage by Antony Lampard after previous lives as a book and 1940 film, Wallace's thriller sends Inspector Tanner to investigate a ruthless murder at Mark’s Priory, the grand ancestral home of the Lebanon family. Soon he discovers that nothing is as it seems: the household is controlled by the family physician, the footmen behave more like guests than servants and the secretary Isla is afraid for her life. As Tanner moves closer to the heart of the mystery, he uncovers a shocking and closely guarded secret.

So, Deborah, who is the frightened lady of the title? "It's fairly obvious who she is, but having said that, all the women are frightened to various degrees, including my character [the widowed Lady Lebanon], though I can't say too much! The young beautiful 'frightened lady' doesn't know the truth...whereas Lady Lebanon definitely does."

Describing her character, Deborah says: "Lady Lebanon is the lady of the house, where the play opens with a lovely ball. She's very grand, very obsessed with tradition and the standing of the Lebanon family, which dates back to Agincourt and even earlier.

"I've had an on-going concern that I shall continue to address with Roy [Marsden] about why she's so obsessed. I believe there must have been a tradition in this family of cousins marrying each other to keep the Lebanon bloodline pure."

The Case Of The Frightened Lady is regarded as one of Wallaces's greatest works, but also testifies to his prolific writing practice. "I've got a copy of the original and I think he must have really churned them out at ten a week, because there are errors in the printing, and it's interesting to see what was let by, when nowadays books are proof read and re-read before being published," says Deborah.

What makes Wallace's story work so well? "I think we like testing ourselves, challenging ourselves, whether trying to solve a mystery or playing sport, and we also like to be scared," says Deborah. "At the same time, the story is creaky and old and is a little ludicrous at time, especially if the gun doesn't go off, and the audience like that. And being set in 1932, the production looks fabulous: the footmen are immaculate and the women's clothes are gorgeous."

Deborah, 71, will leave the tour in November for more filming commitments for her role as Wendy Adams in the long-running BBC1 sitcom Not Going Out. "I was originally asked to do The Case Of The Frightened Lady in December last year but was committed to Not Going Out and would have had to miss a week's rehearsals and other bits here and there, so Rula Lenska did the first run of the tour before I eventually took over in May," she says.

What has made Not Going Out so enduringly popular? "Well, it's Lee [Mack], isn't it? He's funny and hugely likeable, and he's continuing the great clown tradition," says Deborah.

"I also had the privilege of working with Brian Rix 100 million years ago and his son Jamie is the producer for Not Going Out, and just like Brian, he's good at surrounding himself with absolutely brilliant people for the show, like Tim Vine, Abigail Cruttenden, Bobby Ball, Sally Bretton, Geoffrey Whitehead and now Hugh Dennis.

"Lee's an absolute joy and everyone loves working with him: every time we turn up for a new series, it's the same crew working on it, so they must love it too."

No doubt, they will all be back when series ten begins shooting in the late-autumn. "And we're already signed up for next year too," Deborah reveals.

The Classic Thriller Theatre Company presents The Case Of The Frightened Lady at Grand Opera House, York, July 9 to 14, and Leeds Grand Theatre, July 23 to 28. Box office: York, 0844 871 3024 or at; Leeds, 0844 848 2700 or

Charles Hutchinson