England's chief medical officer Professor Chris Whitty has issued a stark warning that coronavirus cases "will rise again" as thousands of Brits headed to the beach.
Professor Whitty warned that cases will spike if people do not follow social distancing guidance.
It comes as a major incident was at Bournemouth's beaches as thousands of visitors flocked to the south coast to enjoy the hot weather.
In a Tweet Professor Whitty wrote: "COVID-19 has gone down due to the efforts of everyone but is still in general circulation.
"If we do not follow social distancing guidance then cases will rise again. Naturally people will want to enjoy the sun but we need to do so in a way that is safe for all."
The warning came after thousands of sun seekers headed to the beach as temperatures soared across the country.
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People reported chaos on the roads around Dorset with hours of traffic jams and the council left "completely overstretched".
Extra police have been drafted in amid reports of anti-social behaviour, fights, littering and abuse being hurled at council crews.
One Dorset resident said on Twitter : "Keep away people. Our infrastructure cannot cope at the moment. There is nowhere to go, park, eat, sit or go to the loo. Please stay away. Yours, A Concerned Resident."
Ali Brady wrote: "It's horrific. Gridlock everywhere. People have brought DOGS to the beach - it's 30 degree heat and no shade on all Bournemouth beaches."
Another incident was declared at Formby Beach in Merseyside, where police were called in to break up large gatherings.
Some locals said they were forced to abandon trips with their children as the crowds were so large.
A total of 43,230 people have died with coronavirus in the UK, with 149 deaths reported on Thursday, according to Department of Health figures.
The mercury rose to a scorching 33.3C (91.94F) at Heathrow Airport in west London on Thursday, beating Wednesday's high of 32.6C (90.68F) at the same location.
Health Secretary Matt Hancock also tweeted: "We all want to be outside and enjoying the glorious sunshine but if you are heading out please do it safely and stick to social distancing rules."
Bournemouth East MP Tobias Ellwood echoed calls from Dorset Police and the council for people to stay away and said he had asked the police minister to send additional officers if the force requested it.
