William Haggas is a British Thoroughbred racehorse trainer, based at Somerville Lodge stables in Newmarket, Suffolk. He is the son-in-law of the multiple champion jockey Lester Piggott.He was educated at Harrow and played cricket at Lord's for Harrow against Eton in 1977, 1978 and 1979, captaining the side in the 1979 match. He started his working life in his father's textile factory, but quit after three months and headed to Newmarket.