This episode was remade in colour, almost word for word, as The Joker (1967) with Emma Peel in Cathy's role. In that episode, Emma drives herself to Devon and Steed follows when he discovers that their old nemesis is on the loose. Consequently, many of the lines spoken by Steed in this version are spoken by Emma in the remake.
Steed's 'new' car is GK3295, a 1930 3 litre Lagonda.
This episode may mark the official start of Steed's love affair with vintage automobiles, as he made reference to having just purchased a "new" car, and was wondering if it would run.
In an interview with Starlog Magazine, Honor Blackman recalled that she got into arguments with director Peter Hammond "because he wanted me to be very tough and ready to kill this man at the end, but I felt so sorry for the character. He moved me so much that I had tears running down my face. Peter was quite cross with me, but I couldn't play it any other way."
The young man played by Kenneth Colley first introduces himself as producer Darryl F. Zanuck, then claims to be Alfred Hitchcock.