Shop price inflation picked up speed over the last month, accelerated by the rising cost of non-food items such as DIY and gardening tools, according to a closely watched survey.

Figures from the British Retail Consortium (BRC) and NielsenIQ released on Tuesday revealed that shop price inflation rose to 1.4 per cent year-on-year in September, up from an annual increase of 0.9 per cent in August and above the previous three-month average of 1 per cent.

Non-food products rose by 0.3 per cent over the last four weeks, fuelled by an increase in DIY and gardening items, the BRC said.

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Food inflation was unchanged for the first time in seven months at 4.2 per cent, but remained elevated. The retail lobby group cautioned that increased labour and energy costs stemming from the £25 billion national insurance raid on the corporate sector continued to push up prices for many farmers, with dairy and beef prices remaining high. The official food inflation measure from the Office for National Statistics hit a 19-month high of 5.1 per cent in August.

On an annual rather than monthly basis, prices for non-food items fell by 0.1 per cent, but the rate of disinflation slowed markedly from August’s 0.8 per cent yearly drop. There is concern at the Bank of England that rising grocery bills and food price inflation will fuel inflation in other areas of the economy.

“A year and a half of non-food deflation looks set to come to an end, as inflationary pressures spread beyond food,” Helen Dickinson, chief executive of the retail consortium, said.

The trade body noted price increases in DIY and gardening products, which enjoyed a rise in demand over the summer due to warmer weather. Prices fell for some back-to-school categories, including laptops, at the start of the new academic year.

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Mike Watkins, head of retailer and business insights at NielsenIQ, said shoppers were becoming “increasingly price-sensitive”.

Pressure on the government has grown before the budget in November. Lord Wolfson of Aspley Guise, the boss of Next and a Conservative peer, has said the chancellor’s policies may cause years of “anaemic” growth. He warned that the medium-to-long-term outlook for the UK economy did “not look favourable”.