Continuity mistake: When Lister swings the axe at The Cat and hits the door frame, the axe head bends. When Lister pulls the axe out, its head is fine again. (00:22:30)
Visible crew/equipment: After Lister is attacked by low Kryten, he sneaks through the cargo bay. There is a shot where the camera is following Lister as he sneaks around a corner, if you look at the floor you can see the shadow of the cameraman. (00:14:45)
Audio problem: When the high Lister plays the harp, his fingers are out of sync to what is being played. (00:11:30)
Character mistake: After the crew realise that the matter paddle has made 2 copies of Red Dwarf, Kryten says something along the lines of, "When I threw the machine in reverse...", but it wasn't actually him who threw the machine in reverse, it was Lister. (00:06:55)
Continuity mistake: Just before Kryten chloroforms Lister, Lister's locks jump from behind his back to over his left shoulder between shots. (00:23:40)
Continuity mistake: During the Higher Cat and Rimmer's dance when Kryten says 'and agony in torment' his arms are by his sides. In the next shot, his right arm is raised. (00:11:40)
Revealing mistake: The low Cat's teeth move and wobble in ways they should not be able to when he is first seen. (00:14:10)
Visible crew/equipment: Just before Red Dwarf explodes, there is a shot of Lister. In the background you can see a moving shadow of a crew member on the floor. (00:04:25)
Audio problem: When the high Kryten picks up the bomb, the high Cat can be seen to start speaking but no sound is heard. In the next shot, the high Cat is then smiling. (00:13:30)
Revealing mistake: The pyrotechnic charges are visible under the 'High' Cat and Kryten's robes, before they are shot. There is also a wire trailing behind Kryten and running up his left leg, presumably a means of detonating the charges. (00:12:45)
Revealing mistake: When Lister slams his nose into the door of the cabinet, you can see it is nowhere near it. (00:17:50)
Continuity mistake: After the Cat incapacitates Lister, the Cat complains about his collar being untidy, then steps aside. The next shot shows Lister stood on his own and the Cat is not visible at all. There was no time for the Cat to walk that fast between shots. (00:23:20)
Continuity mistake: When Lister is choking the Cat, he says 'give me a break, Rimmer'; at this point Rimmer is looking at the Cat and Lister, yet in the next shot he is looking at Kryten. (00:22:50)
Continuity mistake: The bottle of chloroform Kryten uses to take Lister by surprise appears from nowhere. (00:23:30)
Revealing mistake: After Starbug lands on the 'high' Red Dwarf, Rimmer is running out of power and starts to fade in and out. However, Cat, who must be standing too close to Rimmer also fades, the backdrop being partially visible through him. (00:08:05)
Visible crew/equipment: When the High Rimmer and Cat dance, in the wide shot a boom mic can be seen at the top of the screen. (00:11:35)
Continuity mistake: When Lister, the Cat and their higher selves are walking down the corridor, the way Lister is facing changes between shots throughout the scene. (00:09:30)
Continuity mistake: When remote controlled Lister is strangling the Cat, his locks are partially over his left shoulder and partially behind his back. When Lister picks up the bazookoid, his locks are all over his left shoulder. (00:23:10)
Continuity mistake: When Lister is sent flying when the crates explode, his hat falls off, but when he sits up he is still wearing it. It then falls off again when the low Lister spits at him, yet he is still wearing it when he rolls away. (00:13:50)
Answer: It's Queen Victoria, someone any Englishman would recognize, and needed no introduction.