Episode #1.6 - S1-E6
Continuity mistake: The district commander wears the rank insignia of a chief superintendent up until the final episode, when he suddenly appears with the insignia of the lower rank of superintendent.
Episode #1.5 - S1-E5
Continuity mistake: The police force in the series is consistently described as the Yorkshire Police, a fictional force (and its name and crest are shown numerous times). However, when the detective superintendent is being interviewed on TV, the on-screen caption says he is from the West Yorkshire Police, the real force that covers the area.
Episode #1.5 - S1-E5
Factual error: Catherine is told she's been recommended for the Queen's Police Medal for Gallantry. This has not been awarded since 1977, when it was replaced by the Queen's Gallantry Medal, which is still awarded.
Episode #1.2 - S1-E2
Continuity mistake: Sarah Lancashire has an eye injury. On visiting her ex-husband the scarring is gone. When she gets up it's back again. (00:50:40)
