Food prices soar 9.5 per cent in a year challenging supermarket claims of cutting shoppers' costs

The increase is the highest for at least 15 years, despite claims by the 'big four' supermarkets that they are making cuts.

The figure for fresh food  -  meat, dairy, fruit and vegetables  -  is up by 10.8 per cent in a year, according to the British Retail Consortium.

Soaring prices are forcing shoppers to cut back

The figures are in line with a survey last week by the Organisation for Economic Cooperation and Development. The group of 30 trading nations found food prices in Britain are rising more quickly than among similar economies.

They also match the soaring trend of the Daily Mail's own Cost of Living Index, which tracks the cost of a shopping basket of essentials.

The BRC's report will challenge the real value of price cuts being made by Tesco, Asda, Sainsbury's and Morrisons. All say the price of some popular products has been slashed. But this is apparently cancelled out by rises on other items.

Meanwhile, the increasing cost of food, fuel, gas, electricity and other essentials is outpacing salary rises, putting the biggest squeeze on living standards since the Seventies.

Mike Watkins, of retail analysts Nielsen, who helped carry out the BRC study, said: 'Fifty-five per cent of people are cutting their grocery spend as other bills increase.'

The figures put total shop price inflation at 3.2 per cent in July  -  up from 2.5 per cent in June. On food, the annual increase has more than quadrupled in 12 months from 2.1 per cent in July last year.

The BRC claims supermarkets are protecting consumers by absorbing some of their increased costs, preventing even higher rises.

However, research for The Grocer magazine showed prices charged by manufacturers to the big stores rose £3.5billion from 2005 to 2007. But the amount charged to shoppers rose by £200million more.

BRC boss Stephen Robertson said: 'Food prices are rising but retailers are keeping increases well below the extra supply and operating costs they face.'

The big four stores have reported a sharp growth in sales of their discount lines, while purchases at budget grocers Aldi, Lidl and Netto are growing at 20 per cent a year.

Meanwhile, demand for dearer organic produce has fallen 8.1 per cent in three months, according to retail analysts TNS, leading to Tesco cutting the cost of organic fruit and veg.

A spokesman said: 'Many organic favourites will be sold for not much more than the price of their standard equivalents. People are feeling the pinch so we want to help.'

• Jamie Oliver has praised Sainsbury's for selling chicken reared to RSPCA guidelines as a first step to phasing out factory-farmed chicken, calling it 'a massive step in the battle for better standards'. He has campaigned to end factory practices such as cramped barns where birds are bred to grow so fast that they develop leg deformities and heart and lung diseases.