With such a huge scope, it is no surpirse that Red Dwarf evolved over time. Series five and six in particular often went with the "monster of the week" format popular with episodic science fiction. While this was a far cry from the bunk room double act scenes of its origins, it did see the introduction of several unique antagonists, the best of which was undoubtedly the Inquisitor. Seen on-screen right from the start, there is no waiting around to be introduced to the titular simulant's raison d'etre of replacing those unworthy of existence. Bringing the idea of an unstoppable time travelling killer robot to a whole new level, details like each person being judged by themselves takes the episode from flawlessly executed, to firmly establishing Red Dwarf's place amongst the sci-fi elite. Going beyond just the idea, you will not find a more perfect exploration of exactly who a show's main characters are, than when the four crew members attempt (or don't) to justify themselves. Another highlight includes Rimmer signing his name with a BSc which stands for Bronze Swimming certificate, Kryten's "don't tell me, I've got it" was inspired by actor Robert Llewellyn's real life trouble with his lines, and the drastic reordering of the timeline was a blessing to any fan who tries to make sense of the show's inconsistencies. Five star rating? It does better than that, it gets fifteen! Which of these episodes is your favourite time travelling episode? Share your picks in the comments thread below.