Set 24 years after the previous episode, this edition was intended to wrap up the storyline but was never in fact aired. Officially internal BBC strike action had led to no time for editing to be completed before its transmission date. Various rumours have provided contrary reasons, including unsatisfactory ageing prosthetics, the wish to avoid upsetting war veterans and the whole storyline potentially scuppering the planned spin-off Kessler (1981).
Natalie notes that the Communists are responsible for the deaths of 137 million people, making the Nazis look like amateurs in comparison. Kessler made a very similar comment in Episode #1.6 (1981), which was likewise written by John Brason.
This episode takes place in September 1969.
Lisa Colbert was born in 1921 and died in February 1943.
Dr. Pascal Keldermans died in 1957.