Price hikes at Sainsbury's have helped fuel an average 2.2% increase in the cost of groceries in the past month, according to The Grocer Price Index.
The index, which is based on a secret list of 100 grocery products, shows that the average price of our trolley of goods across the big four multiples was £180.62 this month, compared with £176.67 in September.
increased from £179.28 to £187.55, up 4.6% - much more than its supermarket rivals.
Tesco's trolley was 1.93% more expensive, Morrisons' 1.64%, and Asda's 0.67%.
Over the course of the month, the GPI charted a price increase on 26 items at Sainsbury's, and a decrease on seven products.
Year-on-year figures also showed Sainsbury's trolley had risen 4.29%, the most of the big four. Tesco's prices rose 3.45%, Morrisons 2.97% and Asda's 0.72%.
The average price of groceries across the big four rose by 2.9% in the past 12 months.
Sainsbury's, which is currently the subject of a takeover bid, said it was surprised by The Grocer's findings.
"We regularly track
thousands of lines against the marketplace and are currently at our most competitive price position this year," said a Sainsbury's spokeswoman.
"Taking the total basket, across all categories, we
believe that we are in line with the average price increase you quoted for this month."
Kevin Hawkins, director general of the British Retail Consortium, said overall food retail price inflation remained low even though the price of certain food commodities had risen sharply.
"Inflationary pressure from retail is low and is no doubt making a big contribution to achieving the Bank of England's target for the Consumer Prices Index" he said.
sainsbury's to move HQ
Sainsbury's is to relocate its Holborn headquarters a few miles across London to King's Cross in 2011 in a bid to reduce central office costs.
The supermarket chain signed a deal with King's Cross Central developer Argent this week, following an 18-month UK-wide search by property consultant Cushman and Wakefield for a new HQ.
The office is to be part of a 67-acre brownfield site redevelopment that will include 1,900 new homes and retail, entertainment and leisure facilities.
"We are pleased to be part of this development and the regeneration of this area," said Sainsbury's chief executive Justin King. "We were attracted to the site as its environmental credentials support our aim to reduce energy use across our business."
Sainsbury's only moved into its current HQ in 2001, but has been burdened by high rents written into a lease that runs until 2025. Sainsbury's plans to sub-let the Holborn office until then.