Market researcher NIQ said online's share of total UK fast moving consumer goods (FMCG) sales dipped to 10.4% over the four weeks to June 17, from 10.9% in May's data set.

Online's share of the total grocery market in Britain was about 7% before COVID-19. It peaked at about 15% during the pandemic but has since come off as shoppers have increasingly returned to stores.

NIQ said online's sales growth over the four weeks was 4.1% year-on-year, while store sales were up 13.4% or up 1.1 billion pounds ($1.4 billion), with 34 million additional store visits.

"These visits would have included smaller baskets, drinks, snacks and refreshments, as shoppers were out and about enjoying the sun," said Mike Watkins, NIQ's UK head of retailer and business insight.

"It's no surprise that online grocery sales have taken a bit of a hit as there was less of a need to order in a big grocery shop."

Sales of sports & energy drinks rose 31%, mineral water sales were up 25, suncare products jumped 74% and ice cream was up 47%.

Total grocery sales rose 12.4% over the four weeks, with sales in the week to June 17 hitting 2.9 billion pounds - the second strongest week this year behind Easter.

Echoing data from rival market researcher Kantar last week, NIQ said German owned discounters Aldi and Lidl remained the fastest growing grocers with sales growth of 22.2% and 18.7% respectively over the 12 weeks to June 17.

Marks & Spencer's sales rose 15.4%, keeping its spot as the fastest growing after the discounters.

Separately, on Tuesday data co-produced by NIQ and the British Retail Consortium showed food prices rose less slowly for a second month in a row in June but at 14.6% the increase continued to represent a big strain on the households of many families.

($1 = 0.7859 pounds)

(Reporting by James Davey; Editing by Aurora Ellis)

By James Davey