THE boss of Hovis and Mr Kipling owner Premier Foods has quit just 18 months into a major turnaround of the debt-laden food group.

The departure of chief executive Michael Clarke, who joined the company from Kraft Foods in 2011, shocked the City as Premier's shares slumped in early trading.

Premier moved swiftly to replace Mr Clarke by announcing the appointment of Gavin Darby, who was the boss of Cable & Wireless Worldwide until its takeover last year. He spent 15 years in senior leadership roles at Coca-Cola before joining Vodafone in 2001.

The company – which plans to close its flour mill at Dunaskin Street in Glasgow with the potential loss of 15 jobs – said Mr Clarke, who is leaving in order to pursue other business opportunities, had delivered the initial turnaround and set the firm on a course for sustainable profitable growth.

However, Clive Black, retail analyst at Shore Capital, could not hide his disappointment at Mr Clarke's departure.

He said: "The remedial work he undertook to fundamentally allow Premier to survive merits commendation. However, that he is going just as the business needs to press on in a new chapter more dependent upon organic growth and trading than structural commercial engineering may be a concern."

Premier has been struggling under a £1.3 billion debt mountain after a spending spree which included Mr Kipling owner RHM, but it looks to be on the mend after a "landmark" £1.4bn refinancing deal last year.

Mr Clarke's turnaround plan for the group included the sale of a number of businesses to focus on eight "power brands", including Ambrosia and Bisto.

He offloaded Sarson's vinegar and Haywards pickles to Japan-ese firm Mizkan last year while the group also said it will close two bakeries with the loss of 900 jobs, having just lost a major £75 million supermarket contract.

Premier chairman David Beever said Mr Clarke and his team had done a "first-class job" in stabilising the business and generating momentum.

Mr Darby will take the top job from February 4. He said he planned to invest a significant sum in Premier shares and looked forward to developing and growing Premier's power brands.

Last year, Mr Clarke called for Britons to support the economic recovery by buying British brands.

In Scotland, Premier employs hundreds of people across sites such as the Duke Street Bakery in Glasgow, a distribution depot at Eurocentral in North Lanarkshire, and bakery ingredients arm Fleming Howden at Newbridge on the outskirts of Edinburgh.

Premier's shares finished the day down 12% at 106p.