‘A friend of mine just saved the world. Her name was Andrea Yates.’ Doctor Who will tell a similar story with more bells and whistles in Turn Left – the world’s fate again hinging on the decision of a ginger. This is an astonishing piece of kid’s television, taking the old City at the Edge of Forever story and making the victim herself the one to make the decision.

Jane Asher is incredible, and Andrea is sympathetic without being particularly nice – like the flash of anger and madness in her eyes as Maria blithely tells her, ‘I’m sorry, Andrea, but you were meant to die’. There’s a longish sequence between her and Alan in the attic, possibly the longest scene not to include the kids, and it hinges on Asher’s Jackanory abilities. She nails it. Even if Roberts does naughtily include a scene of her offering round cakes.

The villainous Trickster is a terrifying creation: eyeless, representative of its methods of cultivating blind chance and random chaos. But there’s something genuinely evil about forcing a child to make a choice that will affect them forever, before they can even appreciate the scale of the consequences. It’s no wonder it became the show’s Big Bad.

Throughout, there’s a sense of everyone upping their game a bit, in response both to a script that gives everyone including Juliet Cowan their best moments (Chrissie’s best bits: ‘Well that’s just ridiculous’ as the Graske chases Alan, and later apologising to Maria for all the times she let her down), and Graeme Harper’s direction, which expertly balances the introspective moments with a sense of scale and disorientation in the limbo void (plucked straight from his unofficial first gig, Warriors’ Gate) and the Maria-less Jackson household. The result can stand alongside any Doctor Who serial.

Next Time: The Lost Boy – Part One