Factual error: When Terry makes a phone call to the garage to see if Eddie is ok, Ingrid the receptionist tells him that unless he wants to see Eddie again he must call a number beginning with 01946. However, in 1971 the entire area code of London began with 01, it wasn't changed until May 1990 where it split into 2 different area codes. As the film is only taking place in London involving all characters, the area code doesn't need to be given unless Lew Vogel was elsewhere.
Factual error: In the scene where you see the underground train arriving in Tottenham Court Road station, the train has a red front. Only one unit of the stock in question had/has that combined with the original silver livery, and it never ran in service with it. Not to mention the fact that it wasn't applied until 2000, if not later. And the first trains used in service with red fronts rolled out of the shops in the 1980s, and this film is set in 1971.
Factual error: They dig a tunnel in West London and should therefore be tunneling through London Clay. But the substance they tunnel through isn't London Clay. The actual crime scene photos in the 'Bonus Features' also show London Clay. Furthermore, the substrate that they do tunnel through would require shoring, but none is used.
Factual error: Michael X said that he was going to Trinidad to "liberate his people." This is rather misleading and gives the impression that Trinidad was still a British colony. Trinidad and Tobago gained its independence from the United Kingdom on 31 August 1962 so whatever people he had there were already liberated. Also, when the MI5 agent went to Trinidad to check the whereabouts of Gale Benson, he should not have had the power to order the police to burn down any building as Trinidad and Tobago is not subject to the powers of The Crown.
Factual error: It's not just the Mercedes that is "ahead of its time" - one of the police Jaguar XJ6's has an M registration, i.e. August 1973 on. It also had visibly rusty door bottoms! -so much for all the vehicles being immaculate. I didn't see the registration on the Jaguar E-type confiscated by the debt collectors, but it was a Series 3, only introduced in March 1971 - so it had a remarkably fast journey to Terry Leather's dodgy used car lot.