Why is it the villains that intrigue us most? “They are mad, bad and dangerous to know,“ explains writer Patrick Prior, “Those evil guys who scare the hell out of us, but at the same time turn us on just a little.

“They go where we dare not go. Through them we can safely explore those deep unspeakable desires we all hold. There is a vicarious thrill in watching the villain do things that repel us yet we find sexy and exciting.“

Crime saga novelist Martina Cole knows more than most about our attraction to the ‘dark side‘: menacing men and cruel women terrorise the pages of her long list of best-sellers, while her millions of readers lap up every release.

This year is the 20th anniversary of the Essex-born 53-year-old‘s writing career, and to mark the occasion, Theatre Royal Stratford East, which has put on a series of productions based on her books, is revisiting the novel that started it all – 1992‘s Dangerous Lady.

The story follows the fortunes of a London Irish gangland family, from the 1950s to the ‘80s. For 17-year-old Maura, life in London‘s underworld is just part of being a Ryan. At first she doesn‘t approve of her brother Michael‘s escalating criminal ambitions but after a devastating love affair destroys all hopes of a normal life, Maura decides to join the family business – and is ready to make her mark. No one thinks a young woman can take on the hard men of London‘s gangland, but it‘s a mistake to underestimate Maura Ryan.

“She perpetrates bad deeds but we feel, somehow, there‘s a moral justification for it because of the way she’s been treated by other people,“ says Patrick who has adapted the novel for the stage. “She doesn‘t start off as a bad character but is driven to being harsh and bad. There‘s that ambiguity – she kills people, so why do I identify with this women? Why do we cheer her on?

“She‘s an anti-hero, where the line between hero and villain can be blurred.“

At more than 500-pages long, with a cast of hundreds, adapting this epic yarn was no mean feat.

“The biggest single challenge is that her novels tend to have vast spans of time“ adds Patrick who has adapted two other novels for the stage. “This one covers 40 years. It takes on an epic quality but you‘ve got to try to make it believable at the same time. If you‘re covering all those decades you don‘t want it to seem like a whistle-stop tour of history – you have to structure it quite carefully.“

Dialogue is also key to Martina‘s style, and she made sure Patrick was aware of it.

“It‘s very important to her that the dialogue remained true to the spirit of her novels,“ he says. “She didn‘t want me messing around with the feel of the dialogue. It can be tricky because you‘re trying to remain constant and faithful. That‘s one of the things I worked very hard at doing – it‘s certainly something I take great pains with. Martina has never complained yet!“

With a revolving stage, stellar cast and crackling dialogue, Dangerous Lady is sure to thrill Martina‘s fans and create new ones too.

“It‘s a strange paradox that the characters we should hate are also the ones we find irresistible,“ adds Patrick. “They hold our fascination.

“There‘s a little part of us that doesn‘t envy their deeds but their grasp of life. They do things that maybe we wouldn‘t ever want to do – but it‘s thrilling to see them do it.“

Dangerous Lady is at Theatre Royal Startford East from Friday October 19 to November 17. Details: 020 8534 0310