Ian McKellen will play an ageing, infirm Sherlock Holmes in a new picture that reunites the actor with film-maker Bill Condon. The pair previously collaborated on the 1998 drama Gods and Monsters, which earned McKellen an Oscar nomination for his role as Frankenstein director James Whale.

A Slight Trick of the Mind, adapted from the novel by Mitch Cullin, is set in 1947 and finds the sleuth living in retirement but still haunted by an unsolved case from half a century before. Variety reports that the film is being scripted by Jeffrey Hatcher, the writer of The Duchess, and is billed as a co-production between AI Film, an offshoot of Icon, and BBC Films.

Following his role in Gods and Monsters, McKellen went on to shoot what would prove his most popular role, as Gandalf in the Oscar-winning Lord of the Rings trilogy. Condon's other directing credits include Dreamgirls, Kinsey and The Twilight Saga: Breaking Dawn. His latest picture, the WikiLeaks drama The Fifth Estate, opens the Toronto international film festival.