Shocking pictures show the scale of the gathering at beaches on the southern coastline as a major incident is declared during a week of hot weather in the UK.
Bournemouth, Christchurch and Poole council said services were “completely overstretched” as huge numbers of visitors defied advice to stay away.
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Visitor’s behaviour has been condemned as ‘shocking’ and ‘irresponsible’ and police have urged people to stay away from the area.
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.”
The council said 558 parking enforcement fines had been issued – the highest on record.
Dorset Police’s Assistant Chief Constable Sam de Reya said: “These are unprecedented times and we are urging people to stay away from the area of Bournemouth beach and other Dorset beaches.
“We continue to work very closely with BCP council and other partners to ensure the safety of the public.
“We are also deploying additional resources to provide increased patrols in the vicinity to help tackle any issues of anti-social behaviour and other offences being committed.
“The declaration of a major incident allows us to bring agencies together so we can take actions available to us to safeguard the public as much as possible.
“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.”
The Met Office has now confirmed it is officially the UK’s hottest day of the year so far.