David Nabarro, the World Health Organization's special envoy on Covid-19, has questioned whether people in the UK are aware enough of the continuing threat of coronavirus.

Speaking after huge crowds gathered during a heatwave and illegal parties were broken up by police, Dr Nabarro told the BBC: "There's a huge sense of pent-up frustration among so many people who feel that they've been confined.

"The only question that I've got is whether or not the British public are sufficiently aware of just how constant the danger is," he said.

But he said he was less concerned by the images of crowds in the open air than by other risks when people are travelling to the beach, perhaps using public transport, or using facilities such as toilets.

"It's not so much what we do when we're out in the open that matters, it's enclosed spaces when we're huddled closely together - that's where transmission seems to pick up," Dr Nabarro said.