The share of the grocery market held by Wal-Mart's Asda increased marginally in the 12 weeks to 17 July, according to market researchers TNS, halting its previous downward trend.

Asda's share of the grocery market was 16.6%, compared to 16.5% in the same period a year ago. "The recent downturn in sales performance for Asda appears to have stabilised," said Peter East, director of TNS Superpanel. "This turnaround may be partly driven by increased levels of price promotional activity," he said.

"Elsewhere, Tesco show little sign of slowing down, continuing to increase sales year on year by an impressive 11%," he said. Tesco's share is put at 30.4% compared with 28.1% a year ago.

"The two largest European Discount supermarkets in Great Britain, Aldi and Lidl are both displaying disappointing growth figures (3 % and 5 % respectively), whilst still ahead of the overall marketplace growth (2%), these figures show a slow down in performance over the last 12 weeks," he said.

"The Somerfield group (which includes Kwik Save stores) is now growing share, up from 5.7% to 5.8% year on year" he said.  "This follows the acquisition of many of the smaller Safeway stores and indicates positive growth further to the period of consolidation of these stores."