In this episode, Roger Allam seemingly refers to his role as DI Fred Thursday in the ITV series Endeavour - the Morse prequel that was first broadcast in 2012, with some very subtle wordplay. In Endeavour, Roger Allam plays the Senior officer, to Morse the lower ranking officer, in exact parallel to Morse, where Morse is the Senior officer, and Lewis is the Junior. "He's Lewis. I'm Morse".