The Co-operative Group CEO Peter Marks issued a robust defence of the ­retailer's problematic ­acquisition of Somerfield, calling it "the best acquisition we've ever made".

Marks told the IGD Convention the expansion had proved vital in letting the group modernise in the worst economic climate he had ever witnessed.

When asked if, with the benefit of hindsight, he would still have made the deal, Marks ­replied: "Unequivocally, yes."

He added: "Until five years ago, The Co-op was going down. We called it the co-operative movement, but we didn't co-operate and it didn't move."

Despite The Co-op's ­success, Marks warned the industry should get used to the brutal economic ­environment. "This just feels worse than the others," he said. "I don't think I have ever seen consumers as squeezed as this."