Revealing mistake: When Miss Dempsey lifts up Gripper Burke and spins him around before throwing him out of the window, you can see that Bernard Bresslaw has been replaced by a dummy.
Continuity mistake: When Mr Snooper tells Robinson that he was trying to give Mr and Mrs Dreery some "good advice", Mrs Dreery can be seen looking towards the ground, but in the next shot she is looking directly at her husband.
Continuity mistake: When Gripper notices Sidney Bliss' clothes while he is talking to Esme, we see the clothes and there is a cream shirt on one chair and a grey suit and an orange tie on another. But when Gripper sends Bertram Muffet crashing into the clothes during the fight in Esme's flat later on in the movie, the chair with the suit and tie has disappeared.
Continuity mistake: When we first see Charles Hawtrey following Sid James through the streets of London, the gap between the two is short, but when Charles goes around a corner and sees Sid walking down a street, the gap has suddenly increased.
Continuity mistake: When Sidney Bliss is doing his speech at the wedding party towards the end of the film, we see Terence and Jenny and there is a champagne holder containing a bottle behind Jenny. But when we see the man next to her putting jelly down the front of his wife's dress, the holder has changed places and is now by the musicians' stand.
Continuity mistake: When Sid James is doing his speech at the wedding party towards the end of the film, you can see that Kenneth Williams has a cake with pink icing next to him, but a few shots later the cake is now in front of the cream pie next to Patsy Rowlands.
Continuity mistake: When Sid James hits the table to tell the violinist to stop playing in order to do his speech at the wedding party, the violinist puts his violin down near the pocket on his dinner jacket, but in the very next shot he is holding the violin near his waist.
Continuity mistake: When the camera pans in on the unhappy couples at the start of the wedding party towards the end of the film, the camera stops at Jacki Piper and she is looking at the pianist and violinist in action, but in the very next shot she is looking at Richard O'Callaghan.
Continuity mistake: When Mr Dreery says "Are you trying to be funny, mate?" to Mr Snooper in his office, he puts both hands on the table, but in the next shot his hands are now by his side.
Continuity mistake: When Percival Snooper says "Some people are far off worse, you know." to Mr & Mrs Dreery in his office, he has his hands clasped together on the desk, but in the next shot he has one hand on his knee and another on the desk.
Continuity mistake: When the lavatory attendant appears and sees Charles Hawtrey looking under the toilet doors, he is initially holding his sweeping brush with his left hand, but in the next shot he is holding the brush with his right hand.
Continuity mistake: Before pushing the doorbell at Joan Sims' flat, Sid James pours water over himself from the fire buckets to pretend that he had tried to drown himself in the canals. You can see that Sid's suit is wet, but when Joan helps him into her flat, his suit now appears bone-dry.
Continuity mistake: When Sid James enters the bar, you can see Charles Hawtrey reading a newspaper and there are two black holes on the back page. When the bartender says "We never get any other kind", we return to Charles and the back page has suddenly changed.
Visible crew/equipment: When Terry Scott parks his car to visit Jenny Grubb, he stops at a Mini and sees a couple kissing in the back. If you look carefully, you can see a shadow of the boom mic in the background.
Continuity mistake: Watch the cake in front of Terry Scott during the food fight sequence. When the man sitting by Jenny puts jelly down his wife's dress you can see that the cake has no cream around it, but in the next shot, cream has suddenly appeared.
Continuity mistake: During the food fight, Adrian says "Keep 'em coming!" and we cut to a waiter who throws a cream pie at him. In this scene, you can see the violinist and his face is covered in cream. But in the next scene, the violinist's face is completely clean.
Continuity mistake: When Charles Hawtrey catches up with Sid James in the toilets, Hawtrey then looks under the toilet Sid is hiding in. Sid James then appears to look over the top and you can see him smiling but you cannot see his hands. In the next close up of Sid, his hands have appeared, and in the next scene when he goes back down again, his hands have disappeared.
Continuity mistake: When Terry Scott is chatting to the Bishop on the train, the view out of the window shows them to be passing through countryside and travelling at high speed, even though in the previous shot the train was only just pulling out of the station.
Continuity mistake: When Mr Bedsop is putting on his fake beard at the photograph booth, you can see there is nothing behind the policeman in the mirror. In the next shot, the policeman is in front of a confectionery machine, and when we return to Mr Bedsop, the machine has gone again.
