By making an ambitious feature film of one of the world’s best-loved operas, Mozart’s 'The Magic Flute', the actor and director hopes to ensure that the words will be audible and the acting as natural as it would be on screen and stage.

Speaking to The Times at the Cannes Film Festival, on a brief visit to meet distributors, he said that foreign languages in operas had been an insurmountable barrier for him. "If you don’t understand the words, you feel excluded."

Accepting that he might just have been unlucky, he said: "It’s like Shakespeare performances. When great, they’re sublime. When bad, they’re ghastly . . . I want to involve audiences emotionally."

Under his direction, during an 11-week shoot that has just come to a close, singers were not "standing out front and singing". In fact, he refused to let them sing a single note until they had taken extensive acting lessons. With an English libretto by Stephen Fry, he has updated the story to the First World War, to represent "the end of an age of innocence and the beginning of a global conflict".

The film has been shot at Shepperton Studios, where Tim Harvey, his regular Oscar-nominated production designer, constructed elaborate sets including battlefield trenches. Insiders said that the footage they had seen was "breathtaking".

The musical director James Conlon conducted the Chamber Orchestra of Europe in a production that showcases rising young opera stars including Joseph Kaiser, Ben Davis and Amy Carson — who graduated from Cambridge last year — and established performers such as René Pape, Thomas Randle, Lyubov Petrova and Silvia Moi. The £14 million film, which Branagh hopes to premiere at Cannes next year, has been funded by the Peter Moores Foundation, a charity headed by Sir Peter, 73, whose family made its fortune with the Littlewoods retail and gambling business. The Liverpool-based patron of the arts has long devoted himself to breaking down barriers to opera.