The latest set of Kantar Worldpanel figures showed that, for the 12 weeks ending 8 July 2012, Aldi and Lidl achieved a record market share of 2.9% each. Aldi saw growth of 26.1% and Lidl saw sales improve by 11.5%.
However, overall the statistics revealed that grocery sales at supermarkets was slowing down, with growth at 2.1% in the period compared to a year ago when growth was at 4.2%.
Edward Garner, director at Kantar Worldpanel, said: "We are seeing big cutbacks by consumers as they continue to respond to this current period of austerity. The success of the discounters, Aldi and Lidl, is a clear example of shoppers watching their purses, with both retailers continuing to surge ahead.
"Once again, they both achieve all-time record shares of 2.9% and remarkable growth of 26.1% for Aldi and 11.5% for Lidl."
The frozen food sector is continuing to be the top-growing food sector, as the big four supermarkets Tesco, Asda, Morrisons and Sainsbury's remain unchanged in market share growth.
Garner added: "Another sign of austerity making an impact is the decline of the premium own-label sector. These products have been in continuous growth since 2008, despite often being more expensive than their brand equivalent. Now, however, they are declining by 6% year-on-year, while economy own-labels, such as Tesco's Everyday Value, are growing at 13%."
Grocery inflation was reported to be 3.8% for the 12-week period ending 8 July 2012, decreasing since the most recent peak of 6.2% in November last year, which has been attributed to lower inflation for fresh produce and falling milk prices.