Emily Blunts first credited appearance at age 20, in the role of farmer Lucy Markham.
The Home Guard was a uniformed militia nicknamed "Dad's Army." Men as old as 65 could join up. 1200 Home Guardsmen were killed in action by German air raids and rocket attacks.
First of nine appearances by Ellie Haddington as the mysterious spymaster Hilda Pierce. She subsequently would also guest star in a similar role in another long-running British detective series, Endeavour (2012), as Millie Bagshot in Quartet (2018).
Captain Philby has the same surname as the British agent who defected to the Soviet Union, (Harold) Kim Philby.
This represents a fourth guest star crossover between Foyle's War (2002) and the Inspector Morse (1987) arc. Years before Foyle's War, Michael Kitchen guest starred in The Death of the Self (1992). Roger Allam and Anton Lesser, who would later co-star in the Morse prequel Endeavour (2012), previously guest starred in Eagle Day (2002). Here, Laurence Fox, who would later star as DS James Hathaway in the Morse successor/spin-off Inspector Lewis (2006), guest stars.