We Have Put Her Living in the Tomb - S2-E2
Revealing mistake: When Victor and Margaret arrive back from her goddaughter's, they find their new wallpaper has been stripped. Margaret then goes up the stairs to bed and through the arch window you can see her stop at the top of the stairs waiting for the scene to end.
Visible crew/equipment: On the train at the start, after everyone has left except Victor and Margret, you can see a boom operator reflected in the door's glass panel. You can see him and it's even more noticeable when he lowers the boom for when Victor sits down. (00:04:05)
Continuity mistake: The amount of beer in the glass that is glued to Victor's head keeps changing.
Revealing mistake: When Victor gets the glass stuck to his head, it's obvious there is a clear piece of plastic to stop the beer spilling out. This is obvious as it never goes past a certain point, but stops instantly.
Revealing mistake: At the start, the background of the country going by when on the train is very obviously a fake. It sticks out like a sore thumb.
The Man in the Long Black Coat - S2-E8
Other mistake: Eric Idle is called Dr Melvin Whale, but according to the subtitles he is called Dr Melvin Mile.
Chosen answer: The episode is 'The Pit and the Pendulum' The first episode of series 4.
James Ransford ★