Peter Salsbury, chief executive of Marks & Spencer, today resigned from the high-street retailer.
His role will be taken over by chairman Luc Vandevelde, the Belgian-born retailer brought in by the group in January.
Mr Vandevelde said trading continued to be "difficult" and "very challenging".
On reflection, the company had gone too far in its price cutting over the summer, he added.
The group's boardroom shake-up also sees Roger Holmes, former chief executive of Kingfisher's electrical division, arrive as managing director of M&S's UK retail division.
City analysts have questioned whether Mr Holmes, who has no experience in clothing retailing, has the experience to turn around this side of the business.
Mr Vandevelde said he was still seeking a global supply chain manager and someone to manage the food business, and had candidates signed up.
But he ruled out former Asda and Wal-Mart European boss Allan Leighton. Mr Vandevelde said he had "no intention whatsoever" of bringing him on board.
The shake-up also brought the resignations of Clara Freeman, executive director for the UK stores and group personnel, and Guy McCracken, executive director of international retail, business systems and information technology.
Comments: Our rules
We want our comments to be a lively and valuable part of our community - a place where readers can debate and engage with the most important local issues. The ability to comment on our stories is a privilege, not a right, however, and that privilege may be withdrawn if it is abused or misused.
Please report any comments that break our rules.
Read the rules hereComments are closed on this article