Kantar Worldpanel has blamed, in part, the Co-operative Group’s sale of 298 stores to McColl’s for a dip in sales and market share after more than two years of growth.

Sales at Co-ops – which includes all stores with Co-op above the door – declined 0.4% in the 12 weeks ending 13 August and its market share fell to 6.3%, according to Kantar Worldpanel’s latest market snapshot. Kantar said the dip was “at least partly attributable to the retailer’s sale of nearly 300 of its stores to convenience chain McColl’s”.

Symbols and independents enjoyed a 3% boost in sales to £504m – the same percentage growth rate as sector leader Tesco – but at 1.9%, symbols’ and independents’ market share fell a percentage point from the equivalent period last year.

This was because their percentage growth rate fell below that for “total grocers” during the period – exacerbated by Aldi’s and Lidl’s ongoing meteoric growth rate as both continue to rapidly open new stores.

Lidl outshone the pace of growth of its German rival Aldi, up 18.9% to £1.3bn and 17.2% to £1.8bn respectively during a period in which Lidl overtook Waitrose to become the UK’s seventh biggest supermarket chain by market share – 5.2% of the market compared with 5.1% for Waitrose.

Iceland put on a 5.2% sales spurt to £550m, giving it 2.1% market share.

Grocery inflation stood at 3.3% during the 12-week period, continuing the trend of higher prices since the 12 weeks to 1 January.

Fraser McKevitt, head of retailer and consumer insight at Kantar Worldpanel, reported that disappointing weather hit summer favourites hard during the past month.

“Ice-cream sales were down 9% as consumers huddled indoors, while sales of burgers slumped by 25% – an £8m loss year on year – as rain dampened the nation’s appetite for barbecues,” he said.

Sausages, in contrast, managed to escape the summer downturn because of what McKevitt said was a growing taste for “posh bangers” as retailers persuaded shoppers that sausages should be enjoyed beyond the barbecue.

Meanwhile, Nielsen’s latest monthly supermarket sales figures show the return of cooler weather and the exodus of people on summer holidays combined to bring a halt to two months of impressive sales growth for the UK’s leading grocers.

Sales grew at 2.5% year on year in the four weeks ending 12 August, compared with 5.1% growth the previous month.

Nielsen reported sales of soft drinks were particularly hard hit, off 6.1% year on year, as was fresh produce, down 1.4%.

But confectionery benefited from the return of cooler weather, up 7% year on year, and packaged grocery, 5.5%.