The billionaire philanthropist has said that "whole houses" on his private island in the Caribbean have been swept away by the storm, leaving it "completely and utterly devastated".

"We took shelter from the strongest hurricane ever inside the concrete cellar on Necker and very, very fortunately it held firm," Branson said in a blog post.

"I have never seen anything like this hurricane. Necker and the whole area have been completely and utterly devastated.

While he and his staff - who he says are all safe and well - are still assessing the damage, Branson said that whole houses and trees have disappeared and that doors and windows have flown "40 feet away."

Branson added that his company have made a donation to the British Red Cross and that a Virgin Atlantic flight to Antigua on Thursday had brought in aid supplies, including blankets and bottled water.

However he urged the British government to send as much help as possible, adding that the British Virgin Islands, where Necker island is located, would need "major help to rebuild people's homes, buildings, livelihoods."

Ruth Bolton, the aunt of two missing British women, has called on the billionaire to help her find her family. Having raised money on GoFundMe to buy satellite phones to contact her nieces, she is trying to find a way to fly them from the UK to Barbuda, where the women live.