UK MOD A Royal Navy member has died in a training exercise in the English Channel on Wednesday evening.
A Merlin Mk4 helicopter ditched during night-flying exercises with the HMS Queen Elizabeth aircraft carrier near Dorset, the navy said.
A spokesperson for the Royal Navy said that there were no other fatalities or serious injuries.
Defence Secretary John Healey says the investigation into the accident has already started.
Three crew members were on board the Merlin Mk4, which ditched – a deliberate emergency landing on water – on Wednesday.
Two were rescued and taken to hospital. They are not believed to be seriously injured.
The BBC understands that the third crew member, who died in the incident, was based at Royal Naval Air Station Yeovilton in Somerset.
Another Merlin helicopter was in the air at the time.
Prime Minister Keir Starmer said he was “deeply saddened to hear of the tragic death of a member of the Royal Navy”.
On a visit to the HMS Diamond destroyer in Portsmouth, Mr Healey told the BBC: “Today is a day to mourn the loss of a valued navy personnel and think about his family, friends and colleagues.
“For everyone connected with the armed forces this is news that people dread.”
First Sea Lord Ben Key said he was “intensely saddened”.
It is understood that HMS Queen Elizabeth, which was also involved in the night-flying exercise, is still working at sea.
The Mk4 is considered one of the advanced amphibious battlefield helicopters. It can carry up to 24 troops and is powered by three engines.
Where did the incident happen?
The Ministry of Defence has not said exactly where the helicopter ditched during the training exercise with HMS Queen Elizabeth, but it has confirmed it was in the English Channel off the coast of Dorset.
Satellite imagery shows an aircraft carrier was about 20 miles (30km) south of the Dorset seaside town of Lyme Regis at about midday on Wednesday.
Marine tracking websites suggest the UK’s second aircraft carrier, HMS Prince of Wales, is in the Mediterranean, near Gibraltar, so it is likely that the ship in the Channel is the Queen Elizabeth.
What is the Merlin Mk4?
The Mk4, or Mark 4, used by the Royal Marines, has been deployed around the world. It is a variant of the Merlin helicopter developed between the UK and Italy.
It is considered the “world’s most advanced amphibious battlefield helicopter”, according to the Royal Navy, and can carry up to 24 troops.
The last accident involving a Merlin helicopter happened in Afghanistan in 2010, according to online news outlet Navy Lookout.
The aircraft, being used by the Royal Air Force at the time, suffered a heavy landing at Camp Bastion, a former British Army airbase in Helmand Province.
The helicopter was being used by the Royal Airforce at the time, no one was killed in that incident.