Steven Esom, head of food at Marks & Spencer, was appointed to the board of directors this week as part of a radical management shake-up in which Sir Stuart Rose was also made executive chairman in addition to his existing duties as CEO.

Esom has been head of food at M&S since joining in June last year from Waitrose where he was MD. His appointment to the board of directors would "significantly strengthen the depth and capability of the board", said Sir Stuart.

Since joining M&S, Esom has made his mark by introducing a comprehensive cooking ingredients range. The range, which will be increased from 150 to 300 products by June, is a major step for M&S towards positioning itself as a one-stop food shop. Esom is also considering introducing brands such as Marmite to M&S stores later this year.

M&S also revealed Esom's predecessor Guy Farrant was leaving after 30 years. Farrant was promoted from head of food to director of retail and outlets in April last year.

He will be replaced by Steve Rowe, who is currently director of home.

Richard Gillies, director of store design, development and procurement, takes up the new role of director of M&S's five-year 100-point green initiative Plan A.

Sir Stuart, who had planned to retire in 2009, will replace Lord Terry Burns as chairman from 1 June and will now remain at M&S until July 2011.

"It is my view, and the unanimous view of the independent directors, that placing Sir Stuart in this new role creates the right leadership structure," said Lord Burns.

"Sir Stuart has the unique skills to continue the challenge of making M&S a world-class retailer."

Sir Stuart added: "In taking on the role of executive chairman, my task will be to guide the business through the next stage of growth."