Asda has guaranteed to sell groceries at least 10% cheaper than all of its major rivals as it battles to win shoppers struggling with VAT and soaring household bills.
The UK's second-largest supermarket group is promising to refund customers in the form of a voucher redeemable in stores if they find their groceries less than 10% cheaper elsewhere from today.
It builds on the retailer's original price guarantee announced in April last year which offered customers the difference in price against its competitors plus 1p.
Under the new deal, shoppers would therefore be refunded 10 if they found their 100 basket for the same price anywhere else.
Customers who found their 100 Asda basket for 95 elsewhere would receive 10% of 95 plus the original 5 difference - a total of 14.50.
Shoppers can check for refunds by tapping their receipt details into the Asda website the day after shopping to find out how much their basket would have cost elsewhere.
The price comparison will be run by the independent MySupermarket.co.uk website.
Asda said the guarantee would cover all of the 15,000 products listed on the MySupermarket price comparison site, including around 7,000 items subject to VAT.
Around 10% of products at Asda are unique to the retailer and are therefore not included in the price checker.
Asda chief executive Andy Clarke said: "Our customers place their trust in us to always have the lowest prices. But from today our price promise is backed by a copper-bottomed guarantee - if the basket of food you buy in our stores is not at least 10% cheaper than each of our major rivals, we'll put our hand in our pocket and give you back the difference.
"The Asda Price Guarantee cuts through all the phoney claims and headline numbers, and shows when it comes to saving people money, we mean business this year."