British clothing-to-food retailer Marks & Spencer on Thursday said co-chief executive Katie Bickerstaffe would depart the company, leaving Stuart Machin in sole charge.

In an unusual move, M&S in early 2022 switched to being led by two CEOs after the retailer fell on hard times. It has since improved markedly, with its share price surging 50 percent over the past 12 months on strong sales.

Machin has always been referred to as CEO, while Bickerstaffe's title was co-CEO.

"I'm very grateful to Katie for her support in seeing M&S through this important period in the reshaping of the business," Machin said in a statement. "We now have a much stronger business."

Bickerstaffe leaves in July "to pursue her board career", the company said.

"I will leave with great memories and a strong sense of achievement," she added in the statement.

Following the announcement, M&S shares were up 0.5 percent at 242 pence on London's top-tier FTSE 100 index.

"Marks & Spencer has a history of revolving doors with its senior management team, but the difference now is that the business seems to have found its groove and the turnaround story is gaining traction," noted AJ Bell investment director Russ Mould.

"It doesn't appear to be a case of someone senior leaving because the strategy isn't working. Machin is the architect behind the retailer's recent success and the fact he remains in the top job will be of comfort to shareholders and the market."