I am astonished that the committed Marxist film director Ken Loach attended the Cannes Film Festival. The incongruity of a class warrior relishing an event so steeped in hierarchy and triviality is hypocrisy writ gigantic. But there Loach was amid the glitz, accepting the Palme D’Or for The Wind that Shakes the Barley, his poisonously anti-British corruption of the history of the war of Irish independence. What will the comrades say?

Never mind the barley. I wish something could shake the intellectual rigidity of a man whose ideas have not changed for 40 years. Since Loach made his name with 1960s classics including Cathy Come Home and Kes, the Berlin Wall has fallen and China has abandoned the socialist path to prosperity on the grounds that it never arrives. But Loach has not changed.

He still treats IRA killers like cuddly hippies, still detests the British State that educated him and pays for his films. Loach leeches from the nation that nurtured his talent and spits back in its eye. Unforgivable? No, he is exercising the very freedom his creed would deny all of us. For that reason alone we should celebrate his success, but laugh at his confusion.

Ken Loach denies that he is a “socialist realist”. He is right. There is not an iota of realism in his support for George Galloway’s Respect movement. His alacrity at winning a prize at Hollywood’s favourite film festival is risible given his commitment to the overthrow of capitalism. It is quaint that he imagines that overtly ideological films can influence politics. The modern masses are too discerning to swallow propaganda.

But while we must mock an old fool who celebrates his prize amid the ruins of his dream of bourgeois democracy overthrown, Ken Loach is not merely ridiculous. He is also talented and, while that talent is his to squander, it is despicable that he now uses it to promote an ideology of hatred. The Wind that Shakes the Barley is not just wrong. It infantilises its subject matter and reawakens ancient feuds.

During the de-Nazification of postwar Germany Leni Riefenstahl, Hitler’s favourite film director, was classified guilty of the lowest degree of complicity with the regime. Riefenstahl did not fully understand the evil cause to which her work contributed. Ken Loach does not deserve such indulgence. He knows precisely what he is doing.