Andy Serkis made an Animal Farm with fart jokes: ‘And it started a culture war!’

The actor and director, whose motion-capture work in ‘Lord of the Rings’ and ‘Planet of the Apes’ made him a star, is no stranger to breaking boundaries in filmmaking... but his radical take on George Orwell’s anti-fascist polemic has proven more divisive than he imagined. He speaks to Annabel Nugent