We have one of Doctor Who’s bleakest tales with Turn Left By this point in Series 4, Catherine Tate had nailed her role as Donna and Turn Left is pretty much her story as Donna is thrown back into an alternate timeline where the simple act of turning left for a different job on just an ordinary day, resulted in her never having met the Doctor which ultimately led to his death and the events of most of Russell’s era spiralling out of control. It’s a very basic but still interesting time travel concept about the butterfly effect of a simple ordinary action having unforeseen consequences later down the line.

The explanation for each alien incident in the Russell era, as well as what happens to certain characters like Martha Jones and Sarah Jane Smith, are a bit on the nose and the episode is as over the top and stupid as Russell T. Davies normally is, which is often off-putting for me, but Catherine Tate and a lot of the co-stars in this really sell this morbidly depressing world that just gets worse and worse. If anything, I felt Jacqueline King steals the show in a lot of her scenes as Donna’s mum, there’s this beautiful shot where during one of the alien incursions, we cut to a shot of Donna’s mum who has this perfect look of feeling broken inside from having to live in this nightmare of a world.
It gets very dark the more it progresses as we see the effects it begins to have on certain people around Donna, including one scene that to this day I’m amazed Russell managed to get away with for what is predominantly marketed as a kids show.

There is a lot of Russell’s usual silliness like Rose Tyler being all enigmatic for the sake of it, speaking of the future in vague foreshadowing, not to mention the accidental continuity error of the Titanic spaceship destroying London when in Voyage of the Damned they made it clear it would destroy the Earth (an episode less than a year before). That’s what happens when you make every episode about the end of the world/universe, sadly Modern Who still hasn’t learned that you don’t need to be big to be impressive.