Factual error: Towards the end of the film, the British slaves are escaping out of the window. As they rush over to the window, one man's costume flies up. Lovely pair of red underpants he's wearing.

Revealing: Near the beginning, Hengist and Horsa are watching a young cave couple dragging each other around. Hengist is pouring Horsa a drink and you can see him pour, raise the jug, then Horsa takes a sip from his cup. All this time it is patently obvious that no liquids are in the vessels.