The weakness of sterling is continuing to drive rising food prices in the UK, industry analysts TNS Worldpanel said today (31 March).

In the 12 weeks to 22 March, food inflation stood at 9.3%, compared with a rate of 8.7% seen in the prior four-week period.

The continuing fragility of the pound is driving commodity prices, TNS said, leading to an increase in grocery prices.

UK grocery sales rose by 5.8% as the market lapped March 2008 figures that included Easter, which fell earlier last year.

"This growth in consumer spending remains below the Grocery price inflation of 9.3% as shoppers continue to seek to manage the impact of higher prices which are still feeding through year-on-year in the Grocery Sector," TNS director Chris Longbottom said.

"Shoppers trading down to lower-priced products, especially within the retailers' own-label ranges, is the main way they are seeking to contain this."

Asda's sales were up 8.5% on the year, taking the Wal-Mart arm's share of the UK market to a "record" 17.5%.

Morrisons, meanwhile, saw its sales climb 7.2%. The UK's fourth-largest grocer took its share of the market to 11.8%, TNS said.

Tesco, the country's largest grocer, saw its share of the market dip year-on-year, falling from 30.8% a year ago to 30.4%.

Sainsbury's share was "constant" at 16.1%, TNS said, after its sales grew by 5.7%.

Discount retailers - Aldi, Lidl and Netto - saw their combined share of the UK market rise from 5.5% a year ago to 5.9%. TNS said "shopper spending" at the three retailers rose 13%.

However, Longbottom suggested that the UK's larger grocers were having some success meeting the challenge of their cut-price rivals.

"There are some signs of a slowdown in this rate of growth, suggesting that the major multiples are becoming more successful in containing this long-term challenge," he said.