From BBC news website today:
Asked about suggestions that police were patrolling the supermarket aisles to see what people were buying, Downing Street said people were allowed to buy whatever they wanted from shops permitted to be open.
"We set out a list of shops which could remain open and if the shops are on that list then they are free to sell whatever they have in stock," the prime minister's official spokesman said.
Police in Cambridge had to clarify a social media post - since deleted - by an "over-exuberant" officer who suggested they were monitoring aisles of "non-essential" goods in supermarkets.
"The force position, in line with national guidance, is that we are not monitoring what people are buying from supermarkets," they said.