Goofs

The head on the pints of beer disappears between shots as Maisie brings them to the bar for the doctor and his companion.

When the driver of the potato truck stops after spilling his load, the locking pins on the tailboard differ between shots.

After he orders a triple, Blaney pays the bartender holding the bill in his left hand (camera showing the bartender's view). The camera switches to Blaney's point of view, and the same bill is in Blaney's right hand.

At the beginning, Blaney is seen finishing the knot on his tie. In the next shot (of him coming down the staircase into the bar), he has the same tie, but the colored stripes are different in the knot.

As Rusk is leaving Mrs. Blaney's office, he takes another bite of the apple (previously shown as mostly green but ripening into red) and sets it on the desk with the green side facing the camera. At the door, as he turns to see if he's forgotten anything, the closeup shows the apple with the red side facing toward the camera when it should be facing away from it.

After the police see the body in the back of the potato truck, they follow it and hit their siren. The truck driver then hits his brakes, and the body falls out of the potato truck. This would not happen. Inertia would cause unsecured items in the truck to continue moving forward if the truck comes to an abrupt halt.

Just after the hotel porter rings the police and says "This is the Coburg Hotel, Bayswater", an 88 bus can be seen pulling up outside. This route doesn't go to Bayswater.

As Richard escapes from the prison hospital, the guard doesn't think it at all odd for him to wear a white coat leaving the hospital, instead he just bids good night. Hospital staff never leave in their work clothes for sanitary reasons.

There is no reason a medical professional would not leave the building in his work clothes, even if it were not the usual thing to do.

After Barbara is murdered by Bob Rusk, he leaves his tie around her throat. If the police had checked the tie for fingerprints, they could have charged/arrested Bob for murder sooner.

Not everything that is touched can be fingerprinted. It's next to impossible to obtain usable latent fingerprints from fabrics, particularly a necktie which gets "scrunched-up" leaving no flat surfaces from which to obtain a print.

There is an obvious body double for Anna Massey in the nude scene - the double has longer, darker hair.

As Richard hot-wires the Austin Cambridge/Morris Oxford, he tears the ignition lock wiring from under the dashboard. All three wires are of the same length and even their insulation is peeled.

After Rusk kills Brenda in her office, she can be seen breathing while Rusk helps himself to some items on her desk.

Although Blaney makes quite a show of smoking in the taxi with Babs, the cigarette is clearly not lit.

The (hanging) camera tracks backward, turning 180 degrees as it goes down a staircase, before going out the front door. As it passes through an internal doorway within Rusk's house, the door frame can be seen sliding back into place after (presumably) sliding out of the way to let the camera pass through it.

Rusk gives Blaney a horse tip. He has no money to bet and it wins at 20-1. It's a 4 horse race. 95% of the money would have to be bet on the other entries. Even the last choice in a 4 horse race would be lower odds. And, Rusk isn't the only person to get a tip on this horse. The odds would be much lower. It would have to be a larger field to pay 20-1.

Mrs. Blaney's secretary, when giving a description of Richard Blaney, clearly says 'blue', but the audio is dubbed to 'green' eyes. Either this was shot prior to casting the actor, or the script was not corrected at the time of shooting and had to be amended in post-production.

Jim tells Rusk in the pub that a lorry load of potatoes will be sent "back up to Lincolnshire tonight". Lincolnshire is 150 miles north of London. However, when a sack of potatoes falls off the back of the lorry, it is seen passing a road sign which shows Iver Heath 2 (miles), Denham 4; left turn arrow: Wexham, Stoke Poges. The distances and left turn indicate that this road is the A412 Uxbridge Road, which is west of London, probably near the junction with Wexham Park Lane. The lorry should not be in this location if it is travelling north from London.

When examining the murder scene at the marriage bureau, a police officer brings the victim's handbag out to Inspector Oxford, who correctly holds it with a handkerchief to keep his fingerprints from contaminating the evidence. He then he sticks his ungloved hand inside and feels around, thus contaminating it with his own fingerprints.