One of the men killed in a helicopter crash in Northern Ireland was a personal friend of Prince Charles, Clarence House confirmed.
Charles Stisted was chief executive of the exclusive Guards Polo Club in Windsor and was known to the Prince, the Duchess of Cornwall and Princes William and Harry.
Mr Stisted, 47, was one of three people killed when a helicopter came down in a remote site in the Mountains of Mourne in Co Down.
A Clarence House spokeswoman said: "The Prince of Wales, The Duchess of Cornwall, Prince William and Prince Harry are all shocked and deeply saddened by this terrible tragedy.
"Their Royal Highnesses' thoughts and prayers are with the families of those killed at this dreadful time."
Mr Stisted, from Windsor Great park in Egham, Surrey, is also listed as non-executive director of polo event managing company - The Polo Agency.
It is thought the helicopter was returning to England following a shooting expedition.
The Agusta helicopter was travelling from St Angelo airport in Co Fermanagh where the passengers had been on a hunting trip, but the aircraft crashed at around 4pm on Saturday at the mountainous Leitrim Lodge Picnic area near Hilltown.
Mountain rescue teams, the coastguard and other emergency services were alerted when a member of the public reported seeing an aircraft in distress, but it quickly became clear that no one had survived the impact.
After a lengthy recovery operation police confirmed that the pilot and his two passengers were killed.
The Times newspaper reported that the helicopter's owner Ian Wooldridge also died in the crash.
A source revealed the downing of the helicopter was being investigated by the Air Accidents Investigation Branch of the Department for Transport.
South Down MP Margaret Ritchie said: "The local community is in absolute shock, but their thoughts are with the families and friends of the victims. Their thoughts and prayers are with them. What should have been a happy occasion has ended in tragedy."
The Mournes area is internationally renowned for its picturesque scenery. The mountain range, set on the coastline of south Co Down, is designated as an area of outstanding natural beauty.
The highest mountain in the range, Slieve Donard, is nearly 3,000 feet high.
But changeable weather patterns along the coast and the presence of the mountains have led to tragedy in the past.
Sinn Fein MP for Fermanagh and South Tyrone Michelle Gildernew said: "The shock of this accident has been felt by people right across Co Down and Co Fermanagh."
Democratic Unionist representative for South Down Jim Wells said he had spoken to many local residents who were saddened by the news. He said the area had suffered a string of incidents which had caused multiple deaths.
In June last year three men were killed when their light aircraft crashed into a field near a private landing strip at Kilkeel, Co Down.
The coastal community has also been hit by fishing tragedies in recent years.
And the death of four police officers killed when their 4x4 vehicle crashed on a winding road near Kilkeel in November 2008 also stunned the community.
Ulster Unionist representative John McCallister said he was shocked by the Mournes helicopter crash.
"This is an absolute tragedy, and my thoughts and prayers are with the families of those affected," he said.
"I must also convey my thanks to rescue teams and the emergency services for their sterling work - we are deeply grateful for their efforts."Reuse content