Three British territories in the Caribbean, Anguilla, Montserrat and the British Virgin Islands have been hit by Hurricane Irma, says Foreign Office minister Sir Alan Duncan.
A humanitarian operation is under way, with a British naval relief team – including 40 Royal Marines and Army engineers – heading to the area.
The UK territory of Turks and Caicos is in the storm’s path and still at risk.
Sir Alan said £12m of disaster relief money has been made available.
The UK has been criticised by some for an “inadequate” response.
People are waking up to widespread destruction across the Caribbean, where Hurricane Irma has reduced buildings to rubble and left at least 10 people dead.
British overseas territories hit:
- Montserrat was “swiped” by the hurricane on Wednesday, Sir Alan said, but fortunately the damage is not severe.
- Anguilla received “the full blast” of the category five hurricane and has suffered severe damage, “in some respects critical”.
- The British Virgin Islands were also not spared the full force, Sir Alan said, suffering “severe damage” and likely to need “extensive” humanitarian assistance.
The small Commonwealth Realm of Barbuda is said to be “barely habitable”, while officials warn that the French territory of St Martin is almost destroyed.
Turks and Caicos, which has a population of 31,500, is expected to be hit on Thursday by Irma.
On Wednesday Sir Richard Branson, who refused to leave his private retreat of Necker Island in the British Virgin Islands (BVI), said he was “retreating to a concrete wine cellar” with his staff as the hurricane approached.
Sir Richard’s son Sam has since said his father is “OK” but there has been “lots of damage” to the island.
Posting an update on Instagram, Mr Branson also said buildings and moorings on the BVI’s main islands of Tortola and Jost Van Dyke had been destroyed.
On Virgin Gorda – the third largest of the 40 islands and islets – there was no cell, power or wifi coverage, he said.
The BVI’s largest private island, Peter Island, “is wrecked”, he added, though people on the island were thought to be safe.
‘Nuclear bomb devastation’
Britain’s 14 overseas territories are under UK sovereignty and jurisdiction – most are self-governing but they rely on the UK for defence, security and safety – including protection from natural disasters.
Josephine Gumbs-Conner, a barrister from Anguilla, claimed the UK’s preparations for and response to the storm have been “sorely lacking”.
She told BBC Radio 4’s Today programme the UK government should have “done what the French did in St Martin – who made sure that they had military on the ground so that the response given is timely”.
She said the island’s essential services including hospitals and police stations, were now in a “limping position”, after the hurricane caused “nuclear bomb devastation”.
Officials have confirmed several deaths and considerable damage in the French and Dutch territories of Saint-Martin and Saint Barthélemy, popularly known as St Barts.
Foreign Secretary Boris Johnson said he had spoken to the chief minister of Anguilla, while foreign office officials worked through the night to assess and respond to the disaster.
Sir Alan said there are four UK aid experts standing ready to coordinate relief efforts in the region and there will be a meeting of the government’s emergency committee, Cobra, later.
He said Prime Minister Theresa May has spoken to her French counterpart and has agreed to co-ordinate closely with the French and Dutch on relief efforts.
Fears for sisters
Thousands of British tourists are believed to be holidaying in the Caribbean, the travel association ABTA said.
The UK Foreign Office warned Britons to evacuate the area as the most powerful Atlantic storm in a decade approached, but many expats and tourists were left stranded as airlines were forced to ground or divert flights.
Fears are growing for pregnant Briton Afiya Frank, 27, and her sister Asha Frank, 29, who were preparing for the storm in Barbuda but have not been heard from since Tuesday night.
Their aunt, Ruth Bolton, told BBC Radio Suffolk the pair had “gone completely silent” since they last messaged on WhatsApp at about 21:00 GMT on Tuesday.
She said Afiya had been due to return to Suffolk to give birth.
Many British tourists staying at resorts in the Dominican Republic, where a hurricane warning is still in place, are being evacuated from coastal areas and moved to temporary shelters.
Andrea Fowkes Smith, from Surrey, told the BBC that part of the roof had fallen off the hotel where she is sheltering in Punta Cana.
“We have not been evacuated from our hotel but have just been moved to the steak house as our room was on the third floor,” she said.
“They say we should all stay on the ground,” she added. “It’s very strong winds and rain.”
Holidaymaker Marcin Rys, from West Byfleet in Surrey, was eventually evacuated from his hotel near Punta Cana’s beach on Wednesday afternoon, where nearby restaurants and bars had emptied.
“We asked for relocation somewhere further from the ocean but they told us they don’t have any free rooms as everything is taken,” he said.
“But one lady in reception was trying to help and asked us to come back in few hours, once more people have left the hotel.
“She got us a room at 15:00 and we moved.”
The British naval ship, the RFA Mounts Bay, is expected to arrive in the region later on Thursday.
While the French and the Dutch have permanent military bases in the Caribbean, the British forces are kept at sea ready to respond to UK territories spread out across the region.
Meanwhile, British Airways evacuated 326 passengers from Antigua on Tuesday and has managed to rebook many others across the Caribbean islands onto flights out with alternative airlines.
Virgin Atlantic said it has scheduled a relief flight “loaded with essential items” to help the recovery effort, including blankets and bottled water, to arrive in Antigua on Thursday.
Officials in the US have started evacuations of tourists and residents from Florida Keys as the hurricane approaches.
Flights to and from several airports in Florida were being suspended, while Orlando’s international airport said commercial flights would stop from 17:00 local time on Saturday.
A state of emergency had been declared for Florida, Puerto Rico and the US Virgin Islands, mobilising federal disaster relief efforts.