From a Christie’s online article:
Shortly after George Orwell’s death in 1950, his widow Sonia was visited in London by two representatives of the American film producer, Louis de Rochemont. They sought the rights to Orwell’s novel from five years earlier, Animal Farm. It’s said Sonia took some convincing but eventually agreed, on the promise that de Rochemont would introduce her to her hero, Clark Gable.
A conventional, live-action adaptation was out of the question given that the book’s main characters were farmyard animals, so an animated movie was decided upon instead. De Rochemont chose to have it made in the UK rather than the US — partly because of lower production costs, partly because he admired the work of British husband-and-wife duo John Halas and Joy Batchelor, a couple who ran their own animation studio and had produced several propaganda films for the British government during the Second World War.
Their adaptation of Animal Farm was released in 1954, to popular and critical acclaim — the first feature-length animation movie ever made in the UK.
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