Asda has emerged triumphant in The Grocer 33 weekly shopping survey and has been named as Britain’s cheapest supermarket for the seventh successive year.

The chain’s remarkable achievement came despite some serious competition from arch-rivals Tesco and Morrisons.

Asda shrugged off their challenge to record the highest number of cheapest full baskets over the past 12 months and had the cheapest average basket price in three out of the four quarters under review.

Asda boss Tony DeNunzio said: “For us the key challenge is to maintain our price leadership position and we’re very pleased to have won The Grocer 33 for the seventh year running.”

That’s not all. For the second year running, Asda has won our accolade for being best for instore service, having had stores nominated for our weekly Storewatch title 11 times over the year. The Wal-Mart subsidiary narrowly beat Tesco and Morrisons to the award.

When it comes to availability, Morrisons is by far the best. The chain had a near-perfect 99% availability record in the past year, with 36 full baskets in 50 visits, and just 16 out of stocks.

Our survey also provides new evidence to support those who claim the UK’s grocery sector is locked into a dangerous deflationary spiral.

This week, our mystery shoppers were asked to buy the 33 items that appeared on our very first list back in June 1997. The average price they paid for a full basket this week was £36.17 compared to £36.51 back then – a saving of 34p.

And top brands appear to be bearing the brunt. A jar of Nescafé Original 100g which cost £1.99 seven years ago was priced at just £1.63 in the seven chains visited this week, while a 1-litre bottle of Comfort fabric conditioner is up to 13p cheaper in some stores when compared with the 99p paid in 1997. Only one brand – Kellogg’s Corn Flakes – was more expensive.