Speaking as new BRC-Nielsen Shop Price Index figures revealed that food inflation had shot up to a 13-month high in August, director general Stephen Robertson said retailers were “offering more deals”.

He added: ”Milk and bread are particularly competitive battlegrounds. A third of groceries are now on promotion and customers are shopping around.”

Sharp rises in grain prices nudged UK food inflation up to 3.8% in August compared with 2.5% in July, but prices were still “nowhere near” as high as they were two years ago, Robertson stressed.

“We’re nowhere near the return of the double-digit food inflation of two years ago. Despite its recent increase, wheat is over a third cheaper than its peak in 2008, while oil prices are virtually half of what they were back then.”

There was particularly strong inflation in oils and fats, meat, breads, cereals, chocolate and fresh produce, he added.