When Morse examines the old seating-plan, one guest is 'C. Dexter', a nod to the creator of the character.
Describing his career as a schoolteacher, Percy Walsh mentions having taught at Coldwater, the minor public school which is the chief setting for the Season Five closing story, "Icarus".
The line 'she sounds like The Queen Mother', directed at Marion Bailey by the bus driver, is a reference to Marion Bailey's portrayal of The Queen Mother in The Crown (2016) TV series.
When Warren Loomis's strange (and lucrative) skill at predicting the results for football pools is mentioned, he is described as "our very own rocking-horse winner!" - a reference to D.H. Lawrence's famous short story about a young boy who, when seated on his rocking-horse, can predict the results of horse-races as if in a trance. The story was the basis for a British film of the 1940s.
Thursday speculates, fearfully, that his son Sam's disappearance may be as a result of reprisals for "what happened in Ballymurphy last summer". In the space of a few days in the summer of 1971, nine unarmed citizens in the Ballymurphy district of Belfast in Northern Ireland were killed by British troops, whilst a tenth died of a heart attack allegedly brought on by the mistreatment he received at British hands. The youngest of these victims was still in his teens. Fifty years later, it was found that they had all been illegally killed and that claims that any or all of them had been IRA agents were untrue.