Asda and Sainsbury’s have emerged among the top performers in Kantar Worldpanel’s most upbeat assessment for some time of the UK grocery market.

Grocery sales were up 3.9% in the 12 weeks to 7 August against last year, well ahead of the 3.2% rate of inflation. By contrast, Kantar recorded growth of just 2.1% in the previous monthly update.

Outstripping the market this time was Asda, with growth of 6.2%. That boosted its share of the UK market to 17.4%.

Sainsbury’s grew sales by 4.6% over the period, with Waitrose (7.4% growth) also performing well. Discounters Aldi and Lidl continued their momentum with growth of 26% and 11.8% respectively.

“It’s too early to attribute improved grocery sales to the Olympics but the increased market growth rate coincides with the opening week of London 2012 and the better weather in July,” said Kantar’s Fraser McKevitt.

“Shoppers might not yet notice it at the tills, but they are starting to benefit from lower grocery inflation, with prices now rising at the slowest rate for 18 months and a sign that things are starting to look up.“

He added: “Despite this, consumers are still seeking economy products and retailers are reflecting this demand in their store offerings.

“The lowest priced own-label lines, such as Tesco Everyday Value, are growing at 13%, while premium own label sales are falling by 4% year-on-year.”