The sight of Nazi regalia is still startling, especially in this time of rising right-wing populism. So, when a former university building in central London has its interior redecorated with swastikas and eagles, and the red and black pops off the field-grey uniforms of two German soldiers on a fag break, the impact can stop you in your tracks.
History is not repeating itself here. SS-GB, a five-part mini-series adaptation of the Len Deighton dystopian novel of the same name, is taking an alternative view: of Nazi-occupied London in 1941, after Britain loses the war. On the capital's streets, British coppers who formerly policed for the King now uphold the law as dictated by an SS Gruppenführer.
There's a palpable Forties feel on the Metropolitan Polizei HQ set, all ration-book grubbiness and jackbooted oppression. Among the crew's equipment is a "dirt box" on a trolley, full of brushes and pots of earthy powders, ready for a crew member to instantly apply history to props and costumes. Out of sight of the cameras, the production company's signs for toilets and the canteen, gaffer-taped at intervals along corridors, are in the Gothic font indelibly associated with the Nazis (and heavy metal bands).
Along one of those corridors lurks Sam Riley, the show's star, under a grey wool overcoat as suitable for this winter's coat rack as one seven decades previous. "All right?" nods the 37-year-old, who looks barely a day older than he did 10 years ago when he played Ian Curtis in Control. His brilliant turn as the troubled and tragic Joy Division frontman kickstarted a career that, with SS-GB and Ben Wheatley's forthcoming action movie Free Fire, is entering one of its busier periods.
"This role actually came when I was in the middle of one of those panicking dry spells you have as an actor," he explains, "where you start to wonder whether you should have said no to all the things you said no to. My agent told me the story and I loved it; I heard who was directing it [Philipp Kadelbach, noted director of German TV programmes] and found out that he was represented by my wife's agent in Berlin. So I got his number, texted him and said if he hadn't made his mind up about the lead, I'd love to meet him. I stalked him, basically. We went for a coffee and that was it. Plus, James McAvoy was too expensive."
Living in Germany has not dulled Riley's dry Northern wit. He went, as he says, "straight from Bradford to Berlin" to live with the actress Alexandra Maria Lara after they met while making Control. She played Annik Honoré, Ian Curtis's mistress; the two since married and have a son. Now, culturally Anglo-German, he is ideally placed to play Detective Superintendent Douglas Archer of Scotland Yard. His investigating a murder of a black marketeer sparks a greater quest, by both British and German authorities, for the most powerful weapon of all.
"There's a real urgency in finding out what the hell is going on," Riley says, of SS-GB's ramping-up of the dramatic stakes. The show is a welcome reminder of both Deighton — a top-rank spy storyteller often forgotten in the race to canonise Ian Fleming and John Le Carré — and Riley, whose quietly commanding presence is ideally suited for quality-telly intrigue. And SS-GB has a premise that's intriguing and then some: if a German victory in World War II is too terrible to imagine, now you don't have to.