Revealing mistake: The white Datsun, that passes the Bentley during the car chase at the driving test centre, can be seen in the next shot parked in the background.
Other mistake: At the end of this film, at the driving test centre, a blue Austin 1800 is parked out of the way in the background, but in the next scene it is involved in the first of the collisions.
Continuity mistake: During the sequence at the end of the film, when the car chase ends with several collisions at the driving test centre, the vehicles parked in the background change positions between shots.
Continuity mistake: A the end off the film, when the Bentley crashes into the office at the driving test centre it is dry and sunny, then in the next shot the ground is all wet.
Factual error: Several times during the film Sid and Tim talk of taking learner drivers out at the same time. This would be difficult as their driving school only has one car.