Asda crept back to the top this week, undercutting rival Tesco by an impressive margin of £2.42.

The cheapest retailer boasted seven ongoing promotions – the most of all the retailers – and made five reductions. It knocked 6p off its soft-scoop vanilla ice cream and 5p off the ­croissants. There were also 1p reductions on the McCain Home Fries, Pax0 Sage & Onion Stuffing and Scrumpy Jack Cider. A promotion ended on Kettle Chips, however, pushing them up 54p.

Tesco slipped to second place after a promotion ended on Schweppes Tonic Water, pushing it up 19p, and it increased the prices of wafer-thin ham, Quilted Velvet Toilet Tissue and mushrooms by 20p, 34p and 31p/kg respectively. There was a 1p reduction on the Hellmann’s mayonnaise, however.

Morrisons made no price hikes and remained third. A promotion cut Kettle Chips by 55p. Sainsbury's, which stayed in fourth place, made no price cuts and put celery up 10p and Herbal Essences 36p.

It was business as usual for Waitrose, whose £71.99 basket cost £13.47 more than Asda’s. A promotion began on celery, which was down 20p, and it reduced Hellmann’s Mayonnaise by 2p. There was just one price increase – the red pepper was up 15p.