Complex sentence: In 2003, he became the chairman of Michells and Butler, a British company that owns over 2,000 pubs and restaurants, he resigned in 2008 and in June of the same year became the chairman of Cadbury plc, the United Kingdom's largest confectionery manufacturer.
Split into simpler sentences: In 2003, he became the chairman of Mitchells & Butlers, a British company that owns over 2,000 pubs and restaurants. He resigned in 2008 and in June of the same year became the chairman of Cadbury plc, the United Kingdom's largest confectionery manufacturer.