Plot hole: When Bodie and Doyle arrive at World Chemical Products, they meet some of the senior staff in Mr Harvey's office. Revealing that chief chemical analyst Mr Cummings would be able to test the vending machines for the ADX Poison, Harvey appears to pick up the telephone to talk to Cummings, despite the fact he is stood in the very same office.
Continuity mistake: Watch closely during the 'Cowley and a woman' sequence: Bodie and Doyle are travelling in the Capri, but halfway through the scene, it cuts to a shot of a yellow Ford Granada - which gives away the fact the some of the footage was 'lifted' from the earlier episode 7 ("Close Quarters").
Plot hole: Surely it would have made more sense for CI5 to have contacted the demolition team at the girl's hideout, instead of dodging crashing materials and great big demolition balls, ready to smash them to pieces at any moment. (However, this would not have made for as exciting a scene as Bodie and Doyle risking their lives to save the female in distress).
Plot hole: One glaringly obvious script blunder is that the murder of Fitch and Parker is supposed to have taken place "six years previously" (in the summer of 1971, the date established the pre-title sequence) yet Haydon has been in prison for "seven years and five months" according to his daughter. This makes no sense, unless the viewer is to assume that the "present day" sections of the story take place in early 1979. (The episode was first broadcast in February 1978).
Plot hole: The chronology of this episode makes no sense at all in places. For example, the pre-titles sequence makes it clear that it is the summer of 1971, and Doyle mentions to his sergeant that CI5 is being set up. Yet series creator Brian Clemens' own writer's guide specifically stipulated that the CI5 wasn't even conceived until November 1971.