It happens with some epics. Ridley Scott’s American Gangster lasts 2½ hours but gives the impression of having ended before it begins. Our imaginations have barely passed through immigration before we are whirled around early 1970s New York – or a series of heady visual simulacra – by a gifted movie artist who wants to show us his sketches of a city, its teeming corruption and its crusader for truth and justice.

Here is the bribery-prone, Nixon-era NYPD whose lone cuckoo in the nest, Detective Russell Crowe, gets hate looks from colleagues early on when he hands in, rather than embezzling, 1m drug-deal dollars found in a car. And here are the statelier, though no  less speedy, glimpses of heroin king Denzel Washington, the first Afro- American to outplay the Mafia at their own games. For, yes, Richie Roberts (Crowe) and Frank Lucas (Washington) were real-life antagonists. They both survived to tell their tales and to help screenwriter Steven Schindler’s List Zaillian tell his.