Doctor Who: Every Russell T Davies Episode Ranked From Worst To Best

3. Turn Left

What if Donna had never met the Doctor? Well, turns out he wouldn’t have made it out of The Runaway Bride alive!

Cue an alternate timeline where every subsequent invasion takes place unopposed… and the world gradually descends into chaos.

Turn Left is fascinating both as a Doctor Who episode and a piece of drama in its own right. It shows how much worse the world would be without the Doctor (and, by extension, Doctor Who). But it’s also a commentary on fascism, and how easily it takes hold in times of crisis. It's devastating viewing because, like all great stories, there's a kernel of truth at its heart.

Catherine Tate gives her best Doctor Who performance here too, completely and utterly shedding the perception that she was only good at the funny bits – if there were still any doubters remaining by this point.

It's bleak stuff for Doctor Who, and there’s nothing else quite like it. The Time Beetle may look a bit naff – but does anyone care?