A major incident has been declared in Bournemouth after thousands of people flocked to the Dorset coast on the second day of the UK heatwave.
Bournemouth Christchurch and Poole Council said it was “stretched to the absolute hilt”.
Dorset Police has urged people to stay away from the resort and other beaches in the county.
There have been reports of traffic gridlock, anti-social behaviour, fights and overnight camping.
Earlier people were urged to “act responsibly” as temperatures hit the mid-20s.
By mid-morning Bournemouth beach was busy “as far as the eye can see” and the Durdle Door car park was approaching capacity.
Traffic built up early on coast-bound roads and with people having travelled to Bournemouth from as far as Birmingham.
Council leader Vikki Slade said: “We are absolutely appalled at the scenes witnessed on our beaches, particularly at Bournemouth and Sandbanks, in the last 24-48 hours.
“The irresponsible behaviour and actions of so many people is just shocking and our services are stretched to the absolute hilt trying to keep everyone safe. We have had no choice now but to declare a major incident and initiate an emergency response.”
Assistant Ch Con Sam de Reya, of Dorset Police, said people should stay away from beaches in these “unprecedented times”.
“We are also reliant on people taking personal responsibility and strongly advise members of the public to think twice before heading to the area.”
“Clearly we are still in a public health crisis and such a significant volume of people heading to one area places a further strain on emergency services resources,” he said.
Photographs showed beaches and beauty spots heaving with people on Wednesday, which was the UK’s hottest day of the year so far.
David Morley, who lives in Sandbanks, said: “What we saw was a complete breakdown of normal decent behaviour and law and order – it’s completely swamping the system.”
The chain ferry linking Sandbanks and Studland was unable to carry vehicles late into Wednesday evening because of the gridlock on surrounding roads. There was also reports of illegal overnight camping on Bournemouth beach.
Elsewhere along the coast, police at Hove Lawns seafront put a dispersal order in place after a large gathering.
At the scene, Emily Hudson, BBC South
From Bournemouth pier there are thousands of people as far as the eye can see. Some in the sea on inflatables, others sitting on the sand, there are significant [numbers of] gazebos – there is one group of about 50 people.
One man told me he camped in a tent overnight, a lot of people have come from Birmingham – a six-hour round trip. People were telling me they wanted to get “out and about” after lockdown.
It’s incredibly hard to keep social distancing – people are passing each other certainly at less than 2m.
One woman from Birmingham admitted she felt uncomfortable, but said: “You’ve got to understand, after three months lockdown in the city centre, even seeing the sea is worth it.”
Dorset councillor Laura Miller said she was verbally abused and spat at as she directed traffic at Durdle Door on Wednesday.
Roads to the beauty spot were closed after people failed to use the pre-booking parking system.
“Our local industry is dependent on tourism – we’re not saying ‘don’t come’, but come here in a safe and managed way. When it’s too busy, no-one is having fun,” she said.
The car park was approaching capacity again by mid-morning on Thursday.
Current government guidelines state that households can drive any distance in England to parks and beaches.
But Bournemouth East MP Tobias Ellwood said the situation was “very serious indeed”.
“If we are to avoid a second [Covid-19] spike, we have to adhere to these rules – we cannot simply throw them out.
“Right now the beach is one of the few things you can actually do, but you have to do it responsibly – that is individuals recognising we are still in an enduring emergency.”
Earlier this month, both Dorset councils had called on the government to impose travel restrictions, raising concerns that visitor numbers could increase Covid-19 cases in the county.