Junior Marine Nathaniel Burton, 16, drowned in a remote pool on the moor.

The teenager, who was from the south-west of England, was taking part in a river crossing exercise at Crazy Well Pool, near Burrator reservoir.

The incident happened 11 weeks into the 30-week Commando training course, considered to be one of the toughest in the world.

Commando Training Centre, Lympstone

Recruit Burton is the fourth Royal Marine to die in training in the last 30 months.

An inquiry into his death - described as a "tragic accident" by Brigadier David Nicholls - is now under way.

Brigadier Nicholls, Commandant at the Commando Training Centre, Lympstone, near Exmouth, Devon, said Nathaniel was "a very special young man who was halfway through his training and doing well".

He added: "We are all deeply shocked and profoundly saddened by this terrible news and extend our utmost condolences and sympathy to Nathaniel's family and friends."

"There will be a full and very thorough investigation of the circumstances.

"If there is anything we can do to prevent such a tragedy occurring again in the future then we will do so."