It’s a big ask for an audience to spend an entire film in the company of an imposter. When the imposter in question falsely claimed to be a survivor of a Nazi concentration camp, the filmmakers could appear at best foolhardy, or at worst, masochistic. And yet, the true story of Enric Marco – whose fabrications caused a major scandal in Spain in 2005 – is a compelling watch, not least due to a sensational, Goya award-winning performance by Eduard Fernández. Despite some rather plodding storytelling and a nagging ambiguity about Marco’s motivations, Fernández’s tour de force makes for an impressive character study of a warped individual.

Trade unionist Enric Marco becomes a household name in Spain as an advocate for the remainder of the 9000 Spaniards imprisoned by the Nazis. Most of these had fled Spain as Franco seized power and were captured while fighting for the French. At the end of the war, the Falangist regime refused to repatriate them, effectively leaving them stateless. Marco claims to have been interred at the Flossenbürg camp, and his affable personality and gift for spirited oratory leads to him becoming a sought-after figure for lectures, school visits, and memorial events. Eventually he becomes the president of the Amical de Mauthausen, an organisation lobbying for recognition for victims of Nazi war crimes. At the same time, his lies are closing in as sceptical journalist Benito Bermejo (Chani Martín) begins to pull at the threads of Marco’s inconsistent tales.

Aitor Arregi and Garaño’s film is never anything but open about Marco’s position as a liar. Right from the Contempt-echoing opening featuring a clapperboard introducing a take from the film itself, the artifice is highlighted. A recurring motif of Marco dying his bristling moustache further emphasises this. What is ambiguous is whether Marco was a fantasist with a really twisted case of FOMO, or whether there was a more calculating sociopathy at work. It’s a question the film never really gets to grips with, partly because Marco himself proved himself a blustery, slippery character right into his great old age.

What isn’t in doubt is the performance at its centre. Eduard Fernández had already showed his quality during ESFF in another true story, The 47, but you can see why Marco has nabbed him the gong. Even though you know he’s a charlatan, Fernández cuts an engaging, frequently sympathetic. Part of that is spending so long with Marco as the focal point, but there’s a certain twinkle to Marco that makes it more than credible that he was feted by various governments and political groups. With just a small adjustment in ideology, he’d have made a ‘fine’ populist politician.

Ultimately, the film works as the net closes in, and there’s undoubted satisfaction in waiting for Marco to get his comeuppance. Yet, with the motivations for his deceptions seemingly buried with the man, despite speculation from various articles and a novel, there’s a slight void at its heart. Thanks to the central performance it’s always compelling yet one of the lasting impressions is frustration.

Screened as part of Edinburgh Spanish Film Festival