Data from market research group Taylor Nelson Sofres suggest that during June, Asda's share of the grocery market was 16.53%, for the first time overtaking Sainsbury's who laid claim to 16.5% of the market.

Tesco continued to be country's number one, taking 22.9% of the market.

A spokeswoman for Asda stressed that the figures related only to grocery goods such as rice, pasta and canned beans, and did not refer to overall sales volume.

But she said that "it is a first for us and it is really good news".

Rival J. Sainsbury was sceptical about the validity of the figures: "There are lots of different ways of calculating market share, and until we have seen these figures I wouldn't really be able to comment."

And indeed, looking at the overall market share, Sainsbury's comfortably holds on to the number two slot.

Tesco's takes 22.3% of the market, Sainsbury's 17%, while Asda comes third with 12.7%.

Nonetheless, being beaten in the highly competitive grocery market does not bode well for Sainsbury's, especially when considering that Asda recently got a boost when it was taken over by US retail giant Wal-Mart.

Analysts appeared to be relaxed about the survey's results. Neil Currie at Warburg Dillon Reed said that the figures related "only to packaged groceries, not the wider range of groceries where Sainsbury is still clearly in second place with 19.7% of market share compared with Asda at 14.7%".

"Its an indication that ASDA are doing well in this area, but we know that anyway", he added.

Price wars

Consumers, meanwhile, can look forward to the next round of price wars. The Safeway supermarket chain announced that it will cut the prices of 1,000 products by 20%. The cuts will be made for every product in certain categories - starting this week with pizza, pasta and pasta sauce.