Asda this week fired the latest salvo in the supermarket price war with the launch of a price guarantee as it tries to stem its market share decline.

Asda has launched Asda Price Guarantee, which it said “heralds the official end of the grocery price war” and means it “cannot, and will not, be beaten on price”.

The move comes as figures from Kantar Worldpanel show Asda’s market share growth of 2.5% for the 12 weeks to April 28 is lagging its major competitors. Its market share has also dipped from 17% to 16.9%.

The Asda Price Guarantee allows shoppers to go online at the day after their shop to compare the prices of the same products from receipt information with rivals Tesco, Sainsbury’s and Morrisons. The grocer said if shoppers can buy a basket of eight or more comparable products cheaper elsewhere, it will refund the difference, plus a penny more “for good measure”. The price checker is powered by online comparison site

Asda chief executive Andy Bond said: “Our grocery guarantee puts an end to the phoney price wars that most shoppers are sick of.”

Separately, it is understood Walmart Canada boss David Cheesewright has ruled himself out of taking over from Bond at Asda.