Episode #2.2 - S2-E2
Factual error: When Alex leaves the police station at the start of the episode, there is a police liveried Vauxhall Cavalier MK2 with a cross hatched front grille. The episode is set in 1982, and this type of grille didn't appear until the Cavalier was facelifted in 1986.
Episode #2.4 - S2-E4
Factual error: There are several errors relating the photo of Mac and Jarvis at Hendon in 1962. 1) Gene Hunt says that he was at Hendon several years behind Mac. First, he began his career with Manchester Police (he says in the first series that he only transferred to the Met in the last year or two); and only the Metropolitan Police train at Hendon. Second, he was already a DCI by 1973 (as we know from the prequel 'Life on Mars', which is referenced in 'Ashes to Ashes'). There's no way he could have reached DCI in such a short time if he didn't join the police until at least the mid-1960s. 2) Hendon didn't actually open until 1974 anyway; before then, the Met training school was at Peel House in Westminster. 3) Apparently Jarvis left Hendon "in his last year." The Met training course actually only lasted for 17 weeks.
Episode #2.6 - S2-E6
Factual error: The intro to Michael Jackson's "Thriller" is heard, which wasn't released until 30th November 1982, after the setting of this episode.
Answer: Have you finished watching the entire series? I don't think it's fair to answer this for someone who hasn't.
Bishop73