The character played by Richard Pearson in this episode also turns up as a much younger man in an episode of "Endeavour", where he is played by Kevin Trainor.
In the "Endeavour" episode, "Coda", which also features the Jerome Hogg character who appears in this story, there is a young student, glimpsed only briefly, named "Randall" - perhaps the same person as "Randall Rees", the character Martin Jarvis plays here.
Friday Rees is the daughter of an Oxford don, who named her Frideswide, after the city's patron saint.
Only episode of entire run to feature appearance by Lewis's wife, Val.
John Thaw and Jan Harvey had previously appeared together in the Series 3, Episode 13 of The Sweeney, 'On The Run'