Grocery sales at British convenience stores were up 17% year-on-year in the four weeks to June 13, ahead of the 14% growth in total grocery sales, as consumers in coronavirus lockdown prioritised shopping locally, industry data showed on Tuesday.

Market researcher Nielsen said online shopping in lockdown also continued to be popular, with sales soaring 115% compared to the same period last year, and maintaining the 13% share of sales recorded in the previous four-week period.

Nielsen said the average spend per shopping visit across all formats was 20.32 pounds, a decrease of 1.30 pounds compared to the previous four weeks.

Over the 12 weeks to June 13, Iceland outperformed all other major UK grocery retailers with a 23.2% rise in sales year-on-year, thanks to a surge in demand for frozen food products during lockdown.

Sales at the Co-Operative rose 15.9%, outperforming Britain's big four major supermarket groups and reflecting the fact that it operates a network of local convenience stores.

Of the big four, market leader Tesco was the strongest performer with sales up 9.3%, followed by the No. 4, Morrisons, with sales up 8.8% and No. 2 Sainsbury's, whose sales rose 7.2%. Walmart-owned Asda was the laggard, with sales up 3.6%.

As was the case in May's data, the German-owned discounter Aldi lost market share. However, its discounting rival Lidl maintained its share.

(Reporting by James Davey; Editing by Kevin Liffey)