A poster behind the MP in his office refers to a real campaign to free David Cooper and Michael McMahon, imprisoned in 1970 for the murder of a sub-postmaster in a bungled robbery. Their conviction, like Lynn's, depended primarily on evidence from a corrupt senior police officer. After a national outcry the men were released in 1980, but not actually cleared until 2003 by which time both had died.
P.H. Moriarty makes his screen acting debut in this episode but is credited under the name of "Ronald Bonfield".