Doctor Who: Every Tenth Doctor Episode Ranked From Worst To Best

This two-parter doesn't get the credit it deserves. While the premise sounds rather straightforward - it's essentially your typical 'base under siege' story - it's so much more than that once you get into it.

Considering the monster is the Devil himself (or heavily implied to be), the story utilises this and plays with questions of faith and religion among the surviving passengers.

Elsewhere, the other monsters - the rather repulsive-looking Ood - are more than the one-dimensional aliens they appear to be on the surface. As a slave to humanity, issues of free will are discussed, and the age-old lesson 'don't judge a book by its cover' comes up, as the Ood - although they look scary - are friendly and harmless. Well, until the Devil possess them anyway.

Something that definitely is scary is the possessed Toby Zed, with actor Will Thorp giving an incredible performance considering how easily this idea could've come off as laughable.

Matt Jones did a great job writing this story, and it's a shame he never worked on Doctor Who again, although he did write an episode for the second series of Torchwood.