Gareth Roberts has revealed that there’s a distinct “doom-y” feeling in the air during the Series 4 finale of The Sarah Jane Adventures.

The writer, who penned the story with Clayton Hickman, told DigitalSpy that the climax is a “storming” and “emotionally-charged” adventure for Sarah Jane & co. ”I wouldn’t say “armageddon”, but it’s full-blooded and dramatic, to show that children’s television can be like that,” he explained. ”We asked to the director to pretend it was the last one ever!”

Roberts is also behind this week’s episode of Doctor Who, The Lodger (Saturday, 18:45, BBC1/HD!), of which he notes: ”James Corden and Daisy Haggard, who plays Sophie, are both absolutely fantastic, I couldn’t have been happier. When the rushes started to come through, I was jumping up and punching the air.”

The 12-part fourth series of The Sarah Jane Adventures airs this Autumn on CBBC.