Williams was appointed last November by Premier Foods’ chief executive Michael Clarke. He was responsible for directing the restructuring the bakery division – including its Hovis brand.
A Premier Foods spokeswoman said: "Iwan Williams advised the business a while ago that he would like to move on next year to pursue other opportunities."
Yesterday (November 29) Sky News reported Williams’ decision may have been influenced by the appointment last month of Geoff Eaton as chief operating officer.
Speaking at the time, Clarke said: “Geoff’s energy and experience will be critical in helping us unlock value in bread and build further momentum in our grocery division. I very much look forward to working with him.”