After Catherine (Sarah Lancashire) spots the ice cream truck that deals ice cream and drugs, she places a call on her radio about "Operation Greensleeves." "Greensleeves" refers to the famous 16th-century English ballad that the ice cream truck uses as a jingle.
The story that Catherine (Sarah Lancashire) reads to Ryan (Rhys Connah) as she puts him to bed is Cops and Robbers by Janet Ahlberg and Allan Ahlberg.
George Costigan (Nevison Gallagher) & Siobhan Finneran (Clare Cartwright) also worked together on Unforgiven (2009) as Eddie Ackroyd & Izzie Ingram respectively.
Charlie Murphy (Ann Gallagher) & Sophie Rundle (Kirsten McAskill) also worked together on Peaky Blinders (2013) as Jessie Eden & Ada Shelby respectively.