Another knight at the cinema?

Having played Gandalf, Sir Ian McKellen is set to bring life to another literary icon: Sherlock Holmes - in the twilight of his life.

But Arthur Conan Doyle didn’t write about his later years?

Ah, but he did allude to them. And those allusions were worked into a 2005 novel by Mitch Cullin. As a feature-length film, A Slight Trick of the Mind will see the famous detective tackling his last case, aged 63, before retiring to Sussex to keep bees.

Another chapter.

Yes, and fans of the world-famous sleuth may well welcome the shift of focus on to the later years of Sherlock’s life. As a younger man, he’s been reworked every which way possible: from the cheeky chappy of Guy Ritchie’s movies to the cerebral wit played by Benedict Cumberbatch.

So what’s in store?

The film will be directed by Bill Condon, who worked with McKellen on the Oscar-winning Gods and Monsters. He said of the project: “It’s a really great mystery about who Sherlock Holmes is, but it’s also a lovely, delicate movie about what happens as you get older.” McKellen will be cast alongside Truman Show actress Laura Linney as Holmes’ housekeeper, Mrs Munro.

Can’t wait!

Neither can Linney, who is something of a self-confessed Sherlock nerd. “I was obsessed with Sherlock Holmes as a young kid,” she said. “You know how some people are into Dungeons & Dragons? I was into Sherlock Holmes. I loved the atmosphere of the stories. I loved the intrigue, his personality.”

And is it a happy ending for Holmes?

Now that would be telling. But with Holmes battling mental frailty and obsessed by his final unsolved crime, it is safe to say it will be bittersweet. Now, you’ll just have to wait for the film; or pull on your deerstalker and get sleuthing.