Factual error: The show has a BMW X5 (2007 - 2012) appearing when the media goes to the brother's house. (00:27:50)
Episode #2.1 - S2-E1
Factual error: Season 2 is set in 1979. Bill Tench and his wife are leaving the church and going to their car. Behind their car is parked a 1981 Chevrolet Celebrity.
Factual error: DI Renton is a Metropolitan Police officer 'parachuted' into Kent to solve a big case. This hasn't happened for many decades. Local police forces investigate their own crimes without help from the Met.
Factual error: ACC Pat Gallan wears the ribbon of the Queen Elizabeth II Diamond Jubilee Medal. The medal was issued in 2012. Her medals would be correct for 2017 when the series was made, but not 2007 when it is set.
Factual error: A general court-martial is being held. A general court-martial, the highest level of military court, consists of a trial counsel, defense counsel, a military judge, and a panel that must have at least five officers. An enlisted accused can request a panel composed of at least one-third enlisted personnel. In this TV show episode there were only two officers and five enlisted personnel on the panel. (00:40:50)
Episode #1.5 - S1-E5
Factual error: The senior police officer's name tag reads "Assistant Commissioner" but he wears the rank insignia of a Deputy Assistant Commissioner.
Factual error: When Detective Inspector Sara Lunt's photograph in uniform is shown on the TV news she is wearing a double row of silver lace below her hat badge. Only chief constables wear this insignia, well above the rank of inspector.
Factual error: The judge rules in favor of Wendy's father despite not hearing any testimony from his primary witness, who fails to appear. The judge states on the record that he is making this ruling because of the Byrdes' "reputation" rather than any testimony. This is absolutely ludicrous. A judge is not allowed to make a ruling on a child custody case based entirely on his opinion of the litigants, which he doesn't even elaborate upon, rather than any evidence or testimony before him.
Episode #4.9 - S4-E9
Factual error: Renate escapes from the prison in a Morris Ten Four, with the badge visible on the bonnet. However, this designation was not introduced until 1935 and the episode is set in 1931.
Factual error: The provincial police is always described as the Ontario Police Department (OPD) instead of the correct Ontario Provincial Police (OPP).