A former Tiffin School student died after suffering an embolism while snorkelling with the Royal Marines in Egypt, an inquest heard.

Lieutenant Damien Moran, 23, died on Saturday, August 3, 2013 in the last week of a four-week adventure training stint in the eastern city of El Quseir.

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He had been part of a diving expedition organised by 40 Commando Royal Marines, when he was affected by a gas air embolism while snorkelling on a shallow reef as part of a group of six after training had finished for the day.

His lifeless body was brought out of the water but he was pronounced dead on arrival at hospital, an inquest heard today.

Last year his colleague Royal Marine Captain Samuel Shephard was awarded a George Cross bravery award for his heroic efforts in trying to rescue Lt Moran.

The captain had dived into the sea as daylight faded to bring up Lt Moran - who had sunk deep into the water.

At the inquest at West London Coroner's Court today questions were raised about training and safety warnings given to the group.

As a matter of routine Major Mark Attkinson, said: "We would point out to them that you should not do excessive exercise after training."

He added Lt Moran was known to deep dive in levels over 15m deep - something that he was previously warned not to do.

But father Brian Moran said: "My son Day - he would take a risk but he was not a raving lunatic."

Major Innes Catton of the unit that investigated the death said one major finding had been the "anomalies in procedure" for paperwork.

He explained the group had requested the snorkelling approval - which was granted - at "very late notice".

Doctor Ian Calder gave evidence about a post mortem examination where he said the body which he examined had been "fit and well nourished" but there had been a rupture in the lung allowing blood fluid through.

Born on April 5, 1990, Lt Moran - known as "Day" - lived with his family first in Twickenham, then Singapore, before moving to Fern Hill Road in Kingston, where he attended Tiffin School from 2001 to 2008.

He later gained a first class honours degree in marine biology from Southampton University where he also found a passion for water sports.

Lt Moran was commissioned into the Royal Marines in September 2011 and passed for duty in December 2012.

He spent four months serving in Helmand Province as part of Operation Herrick 17, and was in Egypt for his unit’s recovery from the operation.

A statement read out from Brian Moran today said: "Day was happy with life and looking forward to the Egypt trip and a diving trip with his girlfriend."

It added, despite having seen the 'horrors of war', he was still full of optimism.

Lt Moran received a funeral with full military honours at St Peter’s Church in Norbiton where his coffin, draped in a Union Jack, was carried to the soundtrack of The Gael, from movie The Last of the Mohicans, by colleagues.

Recording a verdict of accidental death, Coroner Chinyere Inyama said: "I rarely use the word tragic because all deaths are tragic but this is one of those times the word is appropriate."