The chief executive of biscuit maker Northern Foods has quit after the firm issued a profits warning.
Mr Stewart has been with Northern Foods for 15 years
The Hull-based group said Jo Stewart is to leave the firm after 15 years, with chairman Peter Blackburn to fill his shoes until a permanent replacement can be found.
The firm, which makes ready meals for customers including Asda and Marks and Spencer, is concerned it is "not operating to its full potential", it said in a statement.
The group said higher raw material costs and the hot summer had hit sales at its convenience foods unit.
Mr Blackburn said the firm had "an excellent
product portfolio, strong customer relationships, well invested facilities and a solid financial base".
"It is a business which is capable of delivering consistent growth in earnings and shareholder value," he added.
"However the board believes that the company is not operating to its full potential, and we are seeking a significant improvement in performance.
"It will be the task of the whole management team to achieve this improvement."
The group's five largest customers are Marks & Spencer, Tesco, Sainsbury's, Asda and Safeway.
Although further raw material cost inflation is expected, it said, it expected trends in the key trading period of the second half would be more positive.
The group is set to announce its results on 11 November.