Richard Neely, 38, from the UK, and partner Alison Dalton, 40, an American, drifted for 19 hours off Australia's Great Barrier Reef as rescuers failed to spot them. 

They tied themselves together as they drifted for nine miles after surfacing too far from the boat they had dived off.

Agonisingly, they were quite close to the boat to start with and could see it clearly - but the crew on board had briefed them to surface immediately if they crossed the narrow channel out of the reef. 

When a helicopter finally arrived, its crew could not see them, even though they were nearly overhead. 

Eventually, suffering from hypothermia, they were winched to safety but have caused calls to pay for the rescue, an air-and-sea operation, involving seven helicopters, three aircraft and a fleet of search boats, after Neely sold their story to the British Sunday Mirror. 

After medical checks on nearby Hamilton Island, the exhausted couple were taken by helicopter to Townsville Base Hospital, Queensland, but were released after some rest. 

Neely is no stranger to adversity, while working as a diving instructor in Phuket he was caught up in the tsunami that hit Thailand on Boxing Day, 2004, but he managed to get out of his hotel and reach higher ground. 

Later the diving boat that he was working on sank off Thailand and he was forced to tread water for eight hours through the night until he was picked up by another boat