Continuity mistake: When Sam Twist jumps from the train on the Forth Bridge, he lands in a puddle between the tracks, which are resting on sleepers on top of ballast - but when we see the train disappearing, there are no sleepers or ballast - the rails look like they're on concrete 'runners'. (00:55:00)
Continuity mistake: Near the end of the movie, when George Peppard is talking to Audrey Hepburn in the alley and it's raining heavily, his hair switches between being combed back and combed to the side. Very obvious - this takes place several times.
Continuity mistake: In the cabin when they are coming up with the idea to swap places, Susan has on white sneakers in the beginning of the scene when she is on the bed, and Sharon has on the black Mary Janes. Later in the scene, with no time to change shoes, Susan is seen walking around the cabin wearing the black Mary Janes.
Continuity mistake: The police that come to the aid of the professor are driving an older Ford when they approach than when they arrive to help. The car is a newer model in the later scene.
Continuity mistake: When Carol and Jerry come out of the water on their day at the beach, they sit at the foot of their beach chairs to dry off, then lay back. Miraculously their towels are spread out over the chairs.
Continuity mistake: When Sylvester sees the Daily Bugle newspaper, the front cover headline reads "Police Hunt The Cat." You can see the words THE CAT have nothing around them, but when we see a close-up of the newspaper in the next shot, inverted commas have suddenly appeared.
Continuity mistake: When the Coyote tests his dart bomb, he lights it with a match in his left hand. But when he throws the dart bomb in the next shot, the match that was in his hand has gone.
Continuity mistake: When Sylvester and the dog realise their legs have been connected by a pipe in the junkyard, the position of their feet changes between shots.
Continuity mistake: When Mr Stringer picks up Miss Marple from Akinthorpe Hall in his car, Alexander, as a harmless joke, has tied a string of old shoes and empty cans to the car and put a sign 'Just Married' on the back of the car. As the car first drives off, the sign is seen falling away, but when we get a different shot, the sign is well secured.