Britons spent a record 1.2 billion pounds online buying groceries during a four week period in April and May as they shunned supermarket trips during the coronavirus lockdown, industry data showed on Wednesday.

The online share of 13% of the grocery market in the four weeks to May 16 was up from 7% at the same time last year and 10% higher than in April, Market researcher Nielsen said.

Nielsen said 7.9 million British households placed an online grocery order, up from 4.8 million during the same period last year, including 1.1 million new online shoppers.

While online sales soared 103% year-on-year, sales growth in stores was 6.6%, despite visits to the shops being down 24%.

But the amount shoppers spent on each visit they did make was up 45%, with an average basket value of 21.6 pounds, reflecting a change in behaviour during the lockdown.

"Following over eight weeks in lockdown, UK shoppers are more accustomed to restricted living, and have adapted their grocery shopping habits to match," said Mike Watkins, Nielsen's UK head of retailer and business insight.

"Online has been a clear winner ... as shoppers take advantage of retailers' increased delivery capacity."

Overall UK grocery sales increased by 13% year-on-year, further emphasising a shift to the eat-out-of-home market to the supermarket sector as pubs, cafes and restaurants have been closed during the lockdown.

The biggest gainer during the 12 week period to May 16 was market leader Tesco, with sales up 11.7%, while Sainsbury's, Asda and Morrisons rose by 11.0%, 5.7% and 9.4% respectively.

(Reporting by James Davey; Editing by Alexander Smith)