Goofs

The Scotland Yard detectives put a 'bug' in Tarrant's telephone and leave the telephone with the dial facing the typewriter on the desk. When Tarrant arrives home and checks the telephone, it has been turned 90 degrees and the dial now faces to the right, towards the bed.

At the start of the film where the van is blown up on the motorway, it becomes clear that the scene is filmed on an incomplete stretch of motorway (possibly the M3, which was completed in 1974) as lane markings are missing from one carriageway.

In the roof garden where Tarrant's wife sends the toy fire engine down the slide towards him, as Tarrant turns to re-enter the house, the reflection of the boom mic can briefly be seen in the glass doors behind.