Grocery prices at the big four supermarkets have remained static over the past four weeks, according to The Grocer Price Index.

The cost of our secret 100-item shopping basket has dropped by just 0.1% since 8 January. In the previous survey, the GPI fell 1.3% as January price promotions kicked in.

The cheapest retailer was Asda, at £175.96, followed by Tesco at £176.15 then Sainsbury's at £179.62, with Morrisons the most expensive at £180.77.

Tesco's basket fell most in price, by £2.76.

Sainsbury's and Asda have knocked 16p off and 10p respectively off their baskets over the past four weeks. However, Morrisons went against the grain and added £4.77 to its basket.

"I suspect Tesco and Asda just don't see the point of cutting prices further as the market seems to be moving towards value-added," said Freddie George, analyst at Williams de Broë.