Blooper

There was no legal obligation for shops to close on Easter Monday or other Bank Holidays, and many shops in a resort town like Brighton would have remained open in order to take advantage of the large number of holidaymakers flocking to the town.

Film crew are reflected on Detective Inspector Fellows' Ford Consul as he drives off from the murder house the first time he visits it.

When Fellows and Unwin drive to Greenwich to interview Jean Sherman, they approach her house, having driven from Brighton, along a dead-end road from the direction of the river bank alongside the Cutty Sark.

The shadow of the microphone boom is visible on the wall of Jean Sherman's bedroom when she is left alone in it after Inspector Fellows exits the room the first time.