Trevor Strain, who joined Morrisons in 2009 as commercial and operations finance director and served as chief financial officer before becoming COO in 2019, said he had decided to stand down following the company’s recent change in ownership.

US private equity firm Clayton, Dubilier & Rice has taken over the supermarket chain, which famously began life as an egg and butter market stall in Bradford back in the 19th Century.

Mr Strain said: “This has been a very difficult decision for me but I believe if I am to take on a new challenge for the next few years then it would be better to make that change at the start of the Morrisons journey in private equity, and not in the middle of it.”

Trevor Strain is leaving his senior role at Morrisons

He went on to thank Morrisons CEO David Potts and the staff at the company.

“The pandemic was an incredibly difficult time for everyone, but the way Morrisons rose to that challenge, fed the nation and made sure no-one was left behind, fills me with pride. I wish David and the whole business the greatest success for the future.”

Mr Potts said: “Trevor has played a pivotal role in the turnaround of Morrisons and his contribution to the business over many years has been very significant. I have worked very closely with him since my first day at Morrisons and his ability to plan and execute complex change and progression at great pace has been invaluable.

“Although I am sad that Trevor has decided to leave, I understand and respect his decision. The central role he played during Morrisons performance in the pandemic will be an appropriate and enduring legacy.

"I know I speak for the whole company when I thank him for the huge difference he has made and wish him well for the future.”

Mr Strain’s departure comes a fortnight after Aldi displaced Morrisons in the nation’s ‘Big Four’ supermarkets.

Morrisons had previously held the title of the country’s fourth largest supermarket for 18 years after acquiring Safeway.

But earlier this month, figures from Kantar showed that in the 12 weeks to September 4 Morrisons’s market share has fallen to 9.1 per cent, with Aldi’s rising to 9.3 per cent. At the same point last year, Morrisons had a market share of 9.8 per cent while Aldi was at 8.1 per cent.

Both still trail the dominant big three of Tesco (26.9% market share), Sainsbury’s (14.6%) and Asda (14.1%).

Morrisons claimed the shift had occurred largely for technical reasons.

A spokesperson said: "Market share is partly a function of new store openings and although Morrisons has not put on any significant new space for a while, some competitors are still opening many new stores. But customers don't really care about market share statistics - they care about value, quality, provenance and service and that is where our focus is going to remain."

Senior Morrisons boss departs weeks after Aldi overtakes Yorkshire supermarket chain