British billionaire Richard Branson said Friday he thought he was going to die in a biking accident in the British Virgin Islands earlier this week in which he injured his cheek and tore some ligaments.

Virgin boss Branson, who has built a vast business empire and is known for his daredevil stunts, said the accident happened when he was cycling with his children, Holly and Sam, and hit a bump on a road on the Caribbean island of Virgin Gorda.

"The next thing I knew, I was being hurled over the handlebars and my life was literally flashing before my eyes," the 66-year-old wrote in a blog post, accompanied by graphic photos showing his injuries.

"I really thought I was going to die," he said, adding that the helmet he was wearing probably saved his life. The bike fell off a cliff in the accident.

Branson said he had travelled to Miami for hospital scans but would still be able to take part next month in the biking, hiking and running Virgin Strive Challenge that he was training for.

Branson has set a series of aviation and nautical adventure records, although he failed, despite numerous attempts, to become the first person to circumnavigate the globe non-stop in a balloon.

These exploits brought Branson close to tragedy in 1998 when he and his co-pilot had to ditch their balloon in the Pacific Ocean after low pressure forced the craft down.

His Virgin Galactic space tourism venture suffered a setback in 2014 when a fatal explosion brought down its SpaceShipTwo, killing its co-pilot.

Branson is known as a campaigner for drug law reforms and a string of environmental initiatives.

He was also a key voice in favour of Britain staying in the European Union in the June 23 referendum -- but the vote went the other way with Britons choosing to leave the bloc.

He has owned a paradise island getaway since 1978 in the British Virgin Islands -- a tax haven.