Continuity mistake: In the final scene when Paul gets the lacrosse team to get off the coach, when the camera is inside the coach two girls are off first, followed by the lady teacher. When the camera switches to outside of the coach the same two girls are out of the coach door first but the lady teacher is no where to be seen, and her place is taken by a schoolgirl.
Factual error: In the 1953 sequence the schoolboys in the changing room all have mullet hairstyles that were current when this film was made in 1978, but not for the setting.
Factual error: In the 1953 sequence when the headmaster is driving Fiona and Paul home, the yellow car parked in the road is a Vauxhall Viva HC, which didn't start production until 1970.
Factual error: In the dark ages sequence during the trial of the witches a row of electricity pylons can be seen in the distance.