The new chief executive of UK supermarket group J Sainsbury is reportedly planning a management shake-up as he tries to get the struggling company back on track.

Justin King, the former head of Marks & Spencer’s food business, became chief executive of J Sainsbury today [Monday], replacing Sir Peter Davis who is to become chairman of the company.

King plans to demote Stuart Mitchell, managing director of the company’s UK retail business, a move that may lead Mitchell to quit, reported the Financial Times.

Last week, it was announced that Sara Weller, who was once joint managing director with Mitchell and is now his deputy, is leaving to join UK retailer Argos.

King is reportedly keen to recruit outsiders for the two positions, in order to mark his authority on the company.

Also last week, the group announced it is selling its US business, Shaw’s, to US retailer Albertsons for US$2.5bn.