There’s a scene near the beginning of Imperium that tells you exactly what kind of film it’s going to be. At that exact moment, you’ll decide on the spot whether you’re going to leave the cinema or stick around and submit to pure cinematic enjoyment. It’s all a matter of taste. We stuck around. We submitted. We enjoyed ourselves so much.

Here’s the scene: FBI agent Nate Foster is at home, preparing for an undercover mission. In order to infiltrate a gang of suspected white-supremacist terrorists, he’s got to shave his head; in order to fulfil the mandate of this kind of movie, he’s got to shave his head while standing in front of a big mirror, frowning at his own face, wondering what kind of monster he’s about to become.

Watching this, it’s immediately apparent that Imperium isn’t going to be the kind of journey-into-the-depths-of-one-man’s-soul as claimed by this scene: it’s going to be a deliciously cliff-hanging nail-biting seat-gripping thriller with only occasional hat-tips to psychological anguish. You can go home and watch Tarkovsky’s Stalker if you want magisterial ponderousness. Everyone else: go large with the popcorn.

Foster is persuaded to become an inside man by fellow agent Angela (Toni Collette, acting with wig and chewing gum), and insinuates himself into the neo-Nazi inner-circle. He gets an iron-cross tattoo, he shouts racist slurs, and he swots up on Zionist conspiracy lore. Every so often he gets something slightly wrong – he’s wearing Levis! Jew jeans! – and one of the supremacists makes a ‘…hang on a minute!’ face.

The tension is two-fold. The audience frets: can Nate Foster convince the Nazis that he’s one of them? But also: can Daniel Radcliffe convince us that he’s a real actor? Spoiler alert: with Imperium, Radcliffe continues to put together a catalogue of very interesting performances that might only be appreciated by audiences of some distant future, audiences to whom the Harry Potter films seem as unexceptional and campy as Dragonheart seems now; audiences, basically, who don’t automatically project a lightning-shaped scar onto Radcliffe’s forehead.

Now, at least, they might see a swastika there too. That should make things interesting.