The Co-operative, Aldi and Lidl have continued to make market share gains during the first increase in overall year-on-year supermarket sales since last October, the latest grocery share figures from Kantar Worldpanel show.

The Co-op’s share grew to 6% after an increase in shopper frequency contributed to a 1.9% sales boost, while the discounters’ combined share climbed back to the 10% high they reached before Christmas.

Lidl’s sales grew by 18.9% and Aldi’s by 15.1% in the 12 weeks ending 28 February.

Overall supermarket sales climbed 0.5% year on year, but a 1.6% decline in grocery prices held back further growth.

Sainsbury’s was again the only one of the big four to increase overall spend with sales up for the eighth period in a row at 0.5% - the longest run of sales growth for any of the four main retailers since March 2013.

Strong online sales and its Local convenience stores benefited the group, although its overall share remained flat at 16.8%.

Sales in larger-format stores fell 2% as consumers spent less per average trip in these shop formats - which disproportionally affected Asda. Sales at Asda fell 4% and market share dropped to 16.2% compared with 17% a year ago.

Waitrose sales grew 0.2%, maintaining its 5.2% share of the market for the third consecutive 12-week period. Iceland sales fell by 2.6% and symbols and independents by 2%.

“Despite prices continuing to decline, the combination of Valentine’s Day and consumers stocking up for an early Easter has boosted certain categories,” said Kantar Worldpanel head of retail and consumer insight Fraser McKevitt.

“February chocolate sales are up by 13%, cut flowers have increased by 7%, and sparkling wine sales are up by 15%. New year resolutions to eat more healthily don’t seem to have been forgotten, helping fruit and vegetable revenues grow by 4% despite like-for-like produce prices falling.”

Tesco’s positive run continued with overall sales down 0.8% - halving last month’s decline of 1.6%. A renewed focus on price promotions helped stem the flow of shoppers leaving the retailer, despite the closure of about 50 stores in the last year, McKevitt said.

“Morrisons is also operating fewer stores than last year, which continues to contribute to its falling sales - this month down by 3.2%, with market share dipping to 10.6% from 11% this time last year.

“Online, Morrisons’ sales are growing strongly, a trend set to continue in the coming months as the retailer converts more existing in-store shoppers to its e-commerce channel. Despite being a relative latecomer to online grocery, Morrisons’ forthcoming tie-up with Amazon could provide another boost to the business,” McKevitt said.