Tesco has topped the rankings this week, knocking Asda to second place after undercutting it by 26p.

The cheapest retailer slashed 99p off the honeydew melon in a new promotion, but also made three hikes. It upped fresh cod fillets by 7p/100g and lemons by 2p each, while a promotion ended on Quorn frozen mince, raising it 20p.

Asda surrendered last week's top spot after an 8p hike on the Soreen and promotions ended on Gillette Series Shaving Gel and red seedless grapes, increasing their prices by 69p and 50p/kg respectively. There were no new promotions, but lemons were down 2p each in price.

Morrisons, which remained third, made few price changes. There were no price reductions, but it upped the price of new potatoes by 50p/kg.

Sainsbury's fell two places to fourth, despite three new promotions that reduced the price of Douwe Egberts Smooth Roast Coffee by 73p, Frijj Classic Shake by 58p and Stella Artois by 52p. It also knocked 4p off the price of its lemonade. However the chicken tikka/korma went up 58p after a promotion ended.

Fifth-place Waitrose's basket cost £6.45 more than Tesco's. The retailer knocked 2p off its lemons but a promotion ended on HP sauce, putting it up 45p.