Mark Gatiss’ drama, An Adventure in Space and Time, goes before the cameras shortly, and key castmembers have been announced.

David Bradley, best known as the caretaker Filch in the Harry Potter films, will play William Hartnell. Jessica Raine, star of Call the Midwife, will be Doctor Who’s first producer, Verity Lambert, with Brian Cox, the original Hannibal Lektor, as the show’s creator, Sydney Newman. The director of the first serial, Waris Hussein, will be portrayed by Sacha Dhawan.

“I’m absolutely thrilled,” Bradley said. “I first heard about this role from Mark [Gatiss] while watching the Diamond Jubilee flotilla from the roof of the National Theatre. When he asked if I would be interested, I almost bit his hand off! Mark has written such a wonderful script not only about the birth of a cultural phenomenon, but a moment in television’s history. William Hartnell was one of the finest character actors of our time and as a fan I want to make sure that I do him justice. I’m so looking forward to getting started.”

The 90 minute drama will be part of the ‘takeover of television’ promised by the show’s current head writer, Steven Moffat, and directed by Terry McDonough.