Marks & Spencer ousted his house and clothing boss, Jill McDonald, who spent two years trying to fix the situation.
Executive Director Steve Rowe will succeed McDonald in the short term.
He added that the firm should "tackle the long-standing problems of our clothing and home supply chain with respect to product availability and flow".
Ms. McDonald had previously held roles at Halfords and McDonald.
"His lack of skills in buying clothes and in the supply chain seems to be the problem.But the problem already existed before his arrival, is not it?" Global Data Retail Analyst Maureen Hinton tweeted.
Ms. McDonald joined the company in the fall of 2017.
The appointment of Jill McDonald was a surprise.
The former boss of Halfords had been parachuted into one of the toughest jobs in retail, with no fashion experience.
We were told that she had been hired for her "first-rate customer knowledge" and her experience in managing successful teams. In the end, that was not enough.
Marks & Spencer still has not settled the basics regarding his very important clothing business.
Availability, for example, remains a big problem. It is clear that she was not able to act quickly enough to tackle her longstanding problems.
At present, General Manager Steve Rowe has taken direct control of this division until a successor is found.
This week at the annual general meeting of the firm, Mr. Rowe said the year had been "troubled" for the apparel and home sector.
He said the clothes had malfunctioned, including not buying enough jeans for a promotion in February.
"This has led to the worst availability of casual pants in my life," he said.
However, he also stated that the clothing ranges have improved in terms of fit, style and value.
"I think here we have done a lot of work on style and form and that's the process we need to change," said Rowe.
"The continuation of the work [is needed] to obtain correct size reports, making sure to reduce the number of lines we use [and] focusing on the main lines that are the hallmark of the United Kingdom, "he added.
Rowe said Marks & Spencer had developed a strong apparel team, praising Jill Stanton, director of women and children, and Wes Taylor, director of men's clothing, who had been hired in 2018.
However, he did not mention Ms. McDonald.
After several unsuccessful launches over the past decade, 135-year-old M & S faces challenges in its apparel sector from fashion chains such as Zara and H & M.
In May, M & S announced a third consecutive drop in annual profits and a 1.6% decline in its clothing and comparable home sales. Its shares are down 30% compared to last year.