When Gambit takes the three-wheeled vehicle to chase Henri's lorry, he radios to Purdey that he's heading west. Purdey, who is looking over the area from a tall rooftop, says that Henri is northbound, and tells Gambit to turn left to follow him. This would be impossible, as a left turn would be a turn to the south.
It could be possible that Graeme Henry Wallace was named after former US Vice President Henry A Wallace who in 1948 stood as the presidential candidate for Progressive Party which called for close cooperation with the Soviet Union.
Purdey once went missing for a month in the Brazilian jungle and was found to be living with a tribe of Indians who had saved her life after she was bitten by a tarantula.
Gambit joined the Navy when he was 14 years old.
Steed was awarded the Military Cross.
Purdey can speak Russian.
Anulka Dziubinska, Peter Richardson and Denise Reynolds are usually credited as appearing as guests in this episode. They are even billed in the cast list which appeared in the Radio Times for the week in question. However, they actually appeared in an earlier episode of The New Avengers called Sleeper.
Anulka Dziubinska (who plays Pretty Girl in Taxi) began her career as a model and was Playboy magazine's Playmate of the Month for May, 1973. As an actress, Anulka usually played foreigners. She was in at least six episodes of Vampyres (1974), and was also sometimes credited as Anulka Dubinska.
Purdey says that Gambit's reputation for 'getting around' is common knowledge throughout the Department. The stories about him include the typing pool affair, the under-secretary's under-secretary, and a Russian countess.
Steed is the only person to achieve 100% at the firing range and has done so three times in a row.
The instrument that Steed is playing when his cleaning lady arrives is a Stylophone, a mini-keyboard invented in the late 60s and popular for a while, before becoming something of a joke, due to its rather limited musical range and the tinniness of the noise it made. It was re-released in 2007.
Purdey says her father was shot as a spy ten years ago. She has a stepfather who is a bishop.
Purdey reveals that she was thrown out of the Royal Ballet, where she learnt her high kicks, because she was too tall.