It was a recurring joke onset that the reason for Avon's cynical nature was that when he was a child, his teddy bear was stolen. While filming Blake and Avon's reunion, Gareth Thomas played a prank on Paul Darrow by producing a teddy bear during one take. This caused Darrow and the crew to burst out laughing.
According to Michael Keating, the slime that pours from the damaged Liberator was made from a children's toy that had been banned by The Home Office. The producers bought gallons of the stuff from all over London.
Stephen Pacey accidentally injured Deep Roy during their fight scene. Pacey hurled him up in the air, causing him to break his collarbone when he landed. His injuries, whilst not serious, were sufficient that he could not go on to his next film project.
The meeting between Avon and what he believes to be Blake was also filmed in Pirton Hill, in a nearby church hall. This was because Gareth Thomas had other commitments, which meant he would not be available for the studio recording session.
Lasting for over 54 minutes, this is by far the longest episode of the series. Season one averaged at 51.34, season three 50.89 and season two 50.32 minutes. The season with the shortest episodes was the final season, which averaged at 49.03 minutes and didn't have a single instalment that lasted 50 minutes or above.