Higher wheat and oil prices pushed food price inflation to a 15-month high last month, according to British Retail Consortium/ Nielsen figures.

Food inflation hit 4% in September, from 3.8% in August, while overall shop price inflation increased marginally to a five-month high of 1.9%.

“We are seeing commodity price increases in grain and oils feeding into increased shop prices in grocery categories such as dairy, bread, biscuits and cereals,” Nielsen’s Mike Watkins said.

“And, with consumers remaining cautious about spending, this is coinciding with a slight slowdown in volume sales. So food retailers have compensated by increasing the level of promotional spend in recent weeks.”