Mismatched stock footage of Piccadilly Circus is used. The first shot shows hoardings on the London Pavilion building, which were removed in the 1970s. A later shot shows the Pavilion building without the hoardings.
When Emma was almost hit by a car, she jumped up onto the edge of the wall and then back down onto the floor. When she landed she was facing the theater door, but when Oliver came of the door and the shot changed, she was facing away from the wall. This happened in the transition from stunt person to Angela.
An establishing shot shows Roger Crimmins' office to be in New Scotland Yard. The building, even in this shot, has continuous windows on each floor yet Crimmins' office only has one average sized, discrete window flanked by long sections of walls.
When there is a near miss car accident, a man says "you need a seeing eye dog". In the UK, seeing eye dogs would be referred to as Guide dog.
The streets are too wide for London. Furthermore, in London, the middle lanes are always marked with continuous or broken white lines due to their narrowness, yet none of these markings are present.
When the first scene at Emma's hideaway was shown, obviously the two characters Emma and Jessica were filmed separately on the couch and then the film was put together (as both are played by Angela Lansbury). However, Jessica did a lot of moving while she was talking, so Emma was looking straight across at where she had been, despite her bending down while she talked.
None of the London taxi cabs have their "FOR HIRE" sign lit up. This seems deeply unlikely. If the driver is on duty and has no passengers, he is required by the Carriage Office to switch it on. If he does not, he can be reported and suffer a heavy fine if not loss of his license altogether.
The plane arriving at London airport has no airline name on it, just the words "Boeing 747".
A 1957 Mk1 Jaguar is clearly marked up as a Police car. Although the Police have used Jaguars as police cars, this particular model would be too dated for them to use here.
The type of live music hall variety show as shown in this episode was gone from the British scene by the 1970's.
When singing "Goodbye Little Yellow Bird" Emma blows a kiss to Oliver offstage, but she is still singing the song when she is blowing the kiss. Although it's possible she was pretending as it was part of the act, her voice wasn't even muffled by her hand.
As London's Heathrow airport was developed swiftly after WW2 from an airstrip in a country field, it does not have early Twentieth Century brick buildings crowding opposite its entrance, but a vast acreage of spacious parking.
A double-decker London bus is clearly seen passing the front of Heathrow Airport. These actually service central London and long-hauls across the capital. Instead, the airport is serviced by single-decker buses.
When Jessica first arrives in London and is ambushed by Briggs, she mentions that she needs to talk to Mr. Fielding first and gestures in Fielding's direction as he approaches. At this point, however, she has only heard Fielding's voice over the phone, has not seen him in person, and Fielding has not spoken in this scene. Therefore, Jessica has no way of knowing that the approaching man is Fielding.