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.
Happy Valley (2014)
1 factual error in season 1
Starring: Siobhan Finneran, Charlie Murphy, Sarah Lancashire, Shane Zaza
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.