The conclusion of the episode is shot in the City of London on the street London Wall with the high level walkways and Roman House quite noticeable. In the background you can see buildings of the Barbican Estate under construction.
During the panning night shot of Shaftesbury Avenue in London, William Gaunt's (The Champions) name is in lights on the Appollo Theatre starring in the play 'The Flip Side'. He was the replacement for the part of Theo (previously Patrick Allen) from the 1st August until the 7th September 1968, thereby establishing the period of that film segment.