Filming for this episode was delayed by several months because Lewis Collins (Bodie) was injured in a parachuting accident.
The location used for Cowley's flat is the same building as the one used for the home of a criminal in Season 2 Episode 6, "Rogue". The building is adjacent to the District line bridge, near Putney Bridge station. The road that Bodie and Doyle drive along to reach the building is no longer there as the street has been turned into a walkway.
When Doyle points out that a senior divisional officer has been killed, Detective Sergeant Garbett retorts : " I bl- know that son, I've just had to tell his missus>", as if to suggest he was older than Doyle and Bodie. In fact, the actor who played him, Michael Elphick, was younger than both of the others, Martin Shaw and Lewis Collins.