UK supermarket group J Sainsbury is expected to announce this week the departure of Stuart Mitchell, head of the company's UK supermarket operations.

Mitchell, who has been with the company for 22 years, is believed to have decided to leave soon after Sainsbury's appointed Justin King as its new chief executive, reported The Times.

"It was clear that there was not a job big enough for him to do any more. He is talented and respected, but it was concluded in discussions with Sir Peter (Davis, chairman) and Justin that what he wants to do is no longer in the remit of the job," The Times quoted a Sainsbury's insider as saying.

King is not thought to be looking for replacements for either Mitchell or Sara Weller, former deputy managing director of Sainsbury's who left to become head of retailer Argos.