The poker hand of Aces and Eights is known as the Dead Man's Hand because that is the hand legend alleges Wild Bill Hickock held when he was assassinated. The term "dead man's hand" predates Hickoks death, the composition of the hand varied with place and time. It wasn't until the 1920s that the hand was aces and eights, two each with any kicker. it also wasn't until the 1920s that Hickok was alleged to hold a "dead man's hand" of any kind.
The Lennox farm is the farm also used in the film Children of Men (2006) as the rebel's hideout, and in 28 Weeks Later (2007) as a refuge for those on the run from the infected.
Pip Torrens plays Fergal Jenner in this episode. He returns in episode 18.2, The Incident at Cooper Hill (2016), in the role of Group Captain Jeremy Ford.
Kenneth Cranham (Jude Langham) and Caroline Langrishe (Susan Fincher) also worked together on episode 2.2, An Unholy Death (2013), of Death in Paradise (2011) as Father John and Laura Masters respectively.
Malcolm Storry plays Silas Burbage in this episode. He previously played the role of Joe Megson in episode 4.4, Who Killed Cock Robin? (2001).