Continuity: In Back and Forth, the 'modern' Edmund makes off with the helmet we saw Georgius put on the wall. But in the next shot of the Roman Blackadder and Georgius, the helmet is still where Georgius left it.

Visible crew/equipment: Back and Forth: When Blackadder first goes into the time machine to get the items from Baldrick, and the door goes up, you can see a crew member pushing the door closed, wearing a red shirt.

Continuity: In 'Blackadder Back and Forth', in the Romans scene, we see Stephen Fry enter on a chariot, wearing his helmet, however in the next shot when he is off the chariot, he is carrying the helmet without there being time for him to take it off.

Factual error: In Blackadder's Christmas Carol, during the Elizabethan part of the 1988 Christmas special, Queen Elizabeth asks Edmund if he has any last words before she chops off his head and sticks it on the Christmas tree. Christmas trees weren't introduced to England until Prince Albert (husband of Queen Victoria) brought it from his homeland in 1840.