The Briton, aged 60, was diving off a boat during a holiday with his wife and was found on the ocean floor with his regulator out of his mouth at about 1pm on Friday. He has not yet been named.

Tour operators said the man was lifted on board and the crew, from Quicksilver Cruises, performed CPR but could not resuscitate him. A doctor was later sent via helicopter but was unable to revive the man.

“It was extremely tragic,” a spokeswoman from Quicksilver Cruises told The Telegraph.

“We do not know what the cause of death was at this time. We have no further information.”

The incident occurred about 100 miles north of Michaelmas Cay, where French tourists Jacques Goron, 76, and Danielle Franck, 74, died while snorkelling off a boat at about 11am on Wednesday.

Both had pre-existing medical conditions but the cause of the death has yet to be confirmed.