Discounters such as Aldi, Netto and Lidl are benefiting from the credit crunch as food prices rise and consumers rein in their spending, according to the latest grocery market share data from TNS Worldpanel.

Aldi posted year-on-year sales growth of 18.9% for the 12 weeks to 18 May, TNS Worldpanel said, with virtually all of the growth coming from new shoppers.

Sales were up 9.6% at Lidl and 4% at Netto, while discount frozen-food retailers Iceland and Farmfoods posted sales growth of 12.2% and 10.7% respectively. The best-performing big four grocery retailer was once again Morrisons, up 8.7%, with Sainsbury's the worst, up 4.6%.

Meanwhile, data from Nielsen found that sales in the grocery sector grew 5.2% in the four weeks to 17 May, as a result of the heatwave encouraging spending at the beginning of May.