"Jam sandwich" was a UK slang term for a police car when such vehicles during the 70s and 80s were painted white with an orange horizontal fluorescent strip down the sides, giving the appearance of jam sandwiched between two slices of bread. It was popularised by TV shows such as The Sweeney (1975), Minder (1979) and Only Fools and Horses (1981). (Del says to Rodney after he failed to spot a PC approaching, "You must have been a bit suspicious when a giant jam sandwich pulled up beside you?")
Gene (Philip Glenister), on Jackanory (1965), interrupts Alex (Keeley Hawes)'s thoughts by saying "Shut up ... Shut up, or I'll come round your houses and stamp on all your toys", referencing his own line from Series 1: Episode 1 of Life on Mars (2006).
Gene (Philip Glenister) says "What is this? Smiley's People?" Smiley's People was a novel by John le Carré, the third in a trilogy that began with Tinker, Tailor, Soldier, Spy. The BBC adapted the novel into a six-part TV series, Smiley's People (1982), in 1982 starring Alec Guinness as George Smiley (broadcast 27 September-25 October 1982).
Alex (Keeley Hawes) mentions the Brinks-MAT robbery, which occurred on 26 November 1983. Six robbers broke into the Brinks-MAT warehouse at Heathrow airport, London and stole three tonnes of gold bullion. It was an inside job, with the security guard aiding and abetting the robbers, his brother-in-law being the leader of the gang.
A "sweet spot" is a place where a combination of factors results in a maximum response, originally a sporting term for the spot on a cricket or baseball bat that, when hit, gives the maximum propulsion.