The retailer confirmed a "leadership evolution" following a story by Sky News on Wednesday night that Stuart Machin, who she reported to, would be the sole chief executive following her departure.

M&S said she was to retire following the company's AGM in July.

She has led the digital, data and international aspects of M&S's business during her tenure.

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It has contributed to a turnaround in the company's fortunes across the board since the end of the pandemic.

Mr Machin said: "I'm very grateful to Katie for her support in seeing M&S through this important period in the reshaping of the business. We now have a much stronger business, and she will move on with our very best wishes."

A source told City editor Mark Kleinman that Ms Bickerstaffe had already lined up a new role as a non-executive director of Kingfisher, the DIY retailer which owns B&Q.

She is already a non-executive director of the England and Wales Cricket Board and of Barratt Developments, the FTSE 100 housebuilder.

Before becoming co-CEO alongside Mr Machin, she held other senior jobs at M&S, including as its strategy chief.

Her previous roles include running the UK and Ireland arm of Dixons Carphone and leading SSE's retail energy services division.