As Pelham drives at high speed along the M4 motorway, he passes the same light blue Sunbeam Alpine and a red car at least four times.
Whilst Pelham drives his Rover through London during the opening credits, in some shots the car has black number plates and in others it has reflective white/yellow ones.
During his drive in London and on the motorway it is sunny and the road surface is dry but during the crash the weather changes to dull, then bright and the road surface from dry to wet with, in some shots the wheels splashing in puddles.
Just before Pelham's car crashes near the beginning of the film, he forces a Mercedes to move aside from the outside lane to the middle lane, then within seconds he crashes into a barrier. No such barrier would exist on a British motorway and the sequence of events would have led to the Mercedes crashing anyway had this car not been forced to change lanes by Pelham.
Near the beginning of the film as Pelham is driving erratically in the Rover 3.0 Ltr saloon, the section of motorway is different depending on whether shots are taken at the rear of the car or the front of the car. This can be seen by the presence or absence of white lines (separating the lines of traffic) respectively.
In the opening sequence where Pelham drives at speeds up to 110 mph, he overtakes vehicles going only a bit slower, though the motorway speed limit is 70 mph.
But the 70mph speed limit despite being law is hardly universally abided by on British motorways - especially as the movie was made before speed cameras. So a car travelling at 110mph would typically pass very many cars moving at say or 80mph or 90mph and some would be even faster than that.
But the 70mph speed limit despite being law is hardly universally abided by on British motorways - especially as the movie was made before speed cameras. So a car travelling at 110mph would typically pass very many cars moving at say or 80mph or 90mph and some would be even faster than that.
At the end of the film, when the Rover P5 has fallen into the river, its lights are still lit even when underwater. They would have been short-circuited immediately on entering the water.
When Pelham is playing snooker he pockets a red then pockets the pink then immediately plays on hitting another red ball without re spotting the pink, in snooker, a foul shot.
Pelham leaves his office at the end of the working day opens the unlocked rear door and places his hat and umbrella on the rear seat then opens the drivers door and it can be seen that the window is wide open. No one would leave a car in such an unsecured position.
The shadow of the camera is visible on the office door when Pelham opens it as he rushes off to drive home after speaking to Luigi on the telephone.
The shadow of the camera is visible on Miss Bird when she enters Pelham's office on his first day back after his stay in the clinic.
Judging by the direction taken by his car, Pelham's home is supposed to lie somewhere along the M4 corridor south-west of London, but the actual filming location was near Barnet, to reach which he would have had to drive northwards.
Boom microphone is visible on the back of the club attendant when he approaches Pelham in the snooker room.