The film version of Animal Farm was released to acclaim six decades ago. There was a gala launch at the United Nations in New York in 1954 and the film was praised by national newspapers. "The British out-Disney Disney" was one headline.

George Orwell's novella remains a set book on school curriculums, and his satire has lost none of its relevance in the modern age ("All animals are equal but some animals are more equal than others").

The story of how his book was turned into Britain's first animated feature film is fascinating, not least because the movie was funded by America's Central Intelligence Agency.

The temperamental donkey Benjamin in the film version of George Orwell's Animal Farm

The truth about the CIA's involvement was kept hidden for 20 years until, in 1974, Everette Howard Hunt revealed the story in his book Undercover: Memoirs of an American Secret Agent.

On January 21, 1950, when Orwell died at the age of 46, New Yorker Hunt had been part of the CIA's Psychological Warfare Workshop and he had been sent to obtain the screen rights to Animal Farm from Orwell's widow Sonia.

Some people believe that Hunt exaggerated his own role in sealing the deal – he supposedly promised Mrs Orwell that he would arrange for her to meet her favourite star, Clark Gable – but he was certainly involved in getting the film off the ground.

To add to the Orwellian nature of the story, it is interesting to note that Hunt later found notoriety as part of team that broke into Watergate.

Hunt chose as the film’s producer Louis De Rochemont, the creator of The March of Time newsreel films. They decided to use English film company Halas & Batchelor (run by husband and wife John Halas and Joy Batchelor) as the studio to actually make the film.

Why did the CIA choose England as the place to make the film? They were impressed by the advertisement commercials Halas and Batchelor had made for Kelloggs Cornflakes, and by the wartime propaganda films the couple had been behind.

The pig Napoleon represented Stalin in George Orwell's Animal Farm. He is seen here in the 1954 animated film version

The CIA also thought it would be cheaper to make the film in England and believed, with good reason, that they would be able to keep the English animators in the dark about who was funding the film.

In addition, they didn't trust the political leanings of some American illustrators. And the British government was supposedly happy with a film full of anti-Russian propaganda at a time when the Cold War was in full blast.

Vivien Halas, the daughter of the film’s directors, has said: "I don’t believe that my parents were aware of any CIA involvement at the time."

In the bonus extras for the new high-definition DVD, Howard Whitaker, one of the 80 animators who worked on the film concurred, saying: "We didn't realise at the time. We thought it was just a farm story."

Work on the film began in 1951 and took three years to complete. Watching it 60 years on is an unemotional experience. The satire is still powerful and Napoleon, the tyrant pig who represents Joseph Stalin, is an unforgettable character.

Although the animation is good – grey and grim and completely against the cheery Disney grain – the film itself is a historical curiosity rather than a piece of entertainment.

You are certainly left with admiration for the work of veteran character actor Maurice Denham, who provides the voices of every human and animal in the film.

His angry pig noises are exquisite and it is amusing to consider, in the mix of all the political intrigue, that the main concern from the British authorities was that Denham was making Old Major pig sound too much like Winston Churchill.

Perhaps it's best just to view the film as interesting historical cartoon propaganda, with a memorable plot. The Russians certainly hated the way the film lampooned their secret meetings, and talk of comradeship and five-year plans.

And making a CIA-funded film didn't harm Halas & Batchelor in the long run. They went on to have many commercial and creative successes – including a cartoon series about The Osmonds.

The one person who surely would not have been happy about it all would have been Orwell himself, not least for the way the ending to his novel was changed.

In Orwell’s pessimistic conclusion to Animal Farm, the pigs become indistinguishable from their human masters of old.

In the optimistic CIA-approved ending to the film, the (non-pig) animals ask for help from the outside. They are helped, enabling them to crush the evil Stalin ruler.

Some endings are more equal than others, it seems.



