The teenage son of Princess Diana's lady-in-waiting drowned when he decided to free-dive on a break from work at an exclusive Greek resort.

Henry Byatt may have been tired when he took the plunge in Zakynthos and tragically died on August 6, 2017, it emerged during the pre-inquest review hearing at Westminster Coroner's Court.

The 19-year-old scuba diving instructor, who was working for the Peligoni Club, was found at a depth of 98ft on the seabed of the Ionian Sea.

Free-diving relies on breath-holding underwater rather than proper scuba diving equipment, including oxygen tanks leading questions to be asked over his fateful decision.

His mother Alexandra, who took on the role of lady-in-waiting from 1991 until 1997 for the princess as they were childhood friends, was at the court on Friday along with her senior civil servant husband Duncan, who works in the Cabinet Office and was previously the chief executive at The Foundation of Prince William and Prince Harry from 2009 to 2010.

Senior Coroner Dr Fiona Wilcox, suggested the teenager may have been tired when he decided to go free-diving on a work break with two friends.

Dr Wilcox said: "The police in this case carried out quite an extensive investigation as to whether this was a case that could invite criminal charges or needed to be reported to the Health and Safety Executive.