Food prices leapt by 9.3% after a 7.0% increase in July, driven by increases in products such as milk, margarine and crisps as the war pushed up the costs of animal feed, fertiliser, wheat and vegetable oils, the BRC said.
"We can expect this level of food inflation to be with us for at least another six months but hopefully some of the input cost pressures in the supply chain will eventually start to ease," said Mike Watkins, head of retailer and business insight, NielsenIQ, who co-produces the data.
"However, with further falls in disposable incomes coming this autumn as energy costs rocket again, retail spend will come under pressure in the all-important final quarter of the year."
The Bank of England, which has raised interest rates six times since December, is watching how persistent the surge in inflation is likely to be.
Britain's consumer price index, which measures a broader range of prices than the BRC's data, hit a 40-year high of 10.1% in July.
(Reporting by William Schomberg)
