When Sid James pours water over him from the fire buckets and pretends to have attempted to drown himself in the canal, Joan Sims helps him into the flat, but his clothes appear bone-dry in the next shot.
When Terence Philpot chats with the Bishop on the train, the view out of the window shows them to be passing through countryside and traveling at a high speed, even though in the previous shot the train was only just pulling out of the station.
The position of the remains of the cake on the face of Jenny Grubb changes during the fight at the end of the film.
James Bedsop lowers his paper as Sidney Bliss enters the cocktail bar. He lowers it again in the close up.
The sign outside the Marriage Guidance Bureau depicts 'Citizen's', however, it should actually read Citizens'
When Hattie Jacques smashes the bottle on Sid James head that he'd just bought it's empty as nothing comes out.
When Terence Philpot gets out of his car to visit Jenny Grubb, he looks in the back of the Mini and sees the couple. In the background, you can see the shadow of the boom mic.