Deliberate mistake: In the first few series, it is suggested Lister and Kochanski barely know each other. In 'Balance of Power' Holly says that Lister has only ever spoken 173 words to her. However, by series 4 Kochanski is referred to as Lister's ex-girlfriend with whom he shared a relationship. In the series 4 documentary, Doug Naylor explains that Lister's attitude towards Kochanski was immature in the first series which is why they changed his back story from wanting to be with Kochanski to actually having been with her by series 4.
Timeslides - S3-E5
Deliberate mistake: The Eagle on Hitler's briefcase is that of the (post war) Federal Republic of (West) Germany - not that of the Nazi German Third Reich. This was deliberate - showing the Third Reich Nazi emblem of an eagle holding a swastika would have had the episode banned in Germany, Austria, Poland and any number of other European countries. (00:08:25)