British Board of Film Classification officials told the celebrated director to edit some language in The Angel's Share, and Loach is using his appearances at the Cannes Film Festival to ridicule the "middle class" ratings police.
Competing for Cannes' prestigious Palme d'Or with the comedy, about an unemployed dad-to-be who becomes a whisky taster, Loach told reporters the censors should "pay attention to the manipulative and deceitful language of politics... rather than our ancient oaths and swear words."
He added, "The British middle class is obsessed by what they call bad language, but of course bad language is manipulative language. They're very happy with that. But the odd oath, like a word that goes back to Chaucer's time, they ask you to cut."
The film's producer Rebecca O'Brien adds, "We have made films with heavy scenes of torture and waterboarding and fingernails being torn out - they have been 15 certificates in Britain."
The Angel's Share is Loach's 11th film in competition at Cannes.
The BBFC's 15 certificate is intended to restrict teenagers under the age of 15 from buying a ticket for a provocative or controversial film.