British supermarket group Sainsbury’s has revealed that it is considering lodging a formal complaint with the Advertising Standards Agency (ASA) watchdog over claims by sector giant Tesco that it is 8% cheaper than rivals.

The war of words escalated as both retailers recently unveiled their latest price cuts campaigns. Sainsbury’s has been using celebrity chef Jamie Oliver to publicise its recent £100m worth of in store reductions.

A spokeswoman for Sainsbury’s told the Scottish Daily Record: “We check our prices every week and know we are very close to those of Tesco’s.”

Tesco retaliated with a promise to present evidence today that will back up its claims that it is cheaper. A spokesman from the store told the Manchester Evening News: “We are transparent and publish all of our price cuts on our website so customers can make comparisons.”