In cinemas this week: Dame Judi Dench spied a top role playing Red Joan

Dame Judi Dench has played some extraordinary people in an amazing career – but her latest film may trump them all.

At the age of 84, and a full 20 years after she first played MI6 boss M in Bond movie The World Is Not Enough, she plays the so-called Spy Who Came In From The Co-op.

Joan Stanley is the character inspired by real-life Englishwoman Melita Norwood, who was described as the most important female spy ever recruited by the USSR.

It’s thought the secrets she handed to the Soviets altered the course of the Cold War, and when she was doorstepped by the media in later life, she said she would do it all over again.

Jennie Rooney took her tale and turned it into a book, which has been adapted by Trevor Nunn, and when it came to finding the perfect lady to play Red Joan in later life, it could only be Dame Judi.

For her younger self, Sophie Cookson plays Joan, and both women help produce one of those tales that you would think was too far-fetched if it wasn’t pretty much true.

Stanley is a Soviet sympathiser and pro-communist but manages to get herself a civil service job in England.

Recruited by the KGB in the mid-30s, she then sends them nuclear bomb secrets, with enough detail to help the Soviets keep up with the West – and she continues helping them for more than 50 years.

The real Melita Norwood, Bournemouth-born, died in Wolverhampton aged 93 in 2005.

With a Latvian father, her parents were both very active in socialist circles. Even her neighbours knew her left-wing leanings, but were astonished when the truth finally came out.

It’s thought her communist husband disapproved of what she did, and Norwood never made a penny out of it, but at one point she supplied so much information that the Russians were able to make an exact copy of Britain’s atomic bomb within a year of us making it.

Let’s be honest. Who else could convincingly pull off a role such as this except Judi Dench?

She certainly wasn’t going to turn it down because of her age, insisting: “I don’t really want to retire. I intend to go on working as long as I can, because I still have a huge amount of energy.”

Despite a global reputation such as hers, in fact, she still frets over the offers drying up.

“I just feel incredibly lucky to be employed when there are so many actors and actresses who are not.

“That’s why, you know, I sometimes feel desperate in case I’m not going to be cast again.

“I think you should take your job seriously, but not yourself.

“That is the best combination.”

There is, of course, sadness behind that drive and endless work ethic.

When Michael Williams, her husband of 30 years, passed away in 2001, keeping busy with work helped Judi to cope, and still does.

“Since Michael died I’ve worked constantly. Friends and colleagues are very sustaining. They’re the people who get you through it. It’s no good to be on your own.”

Red Joan is in cinemas from Friday April 19.