A second cousin of the Queen, Lord Mountbatten was Prince Philip’s uncle and much-loved by all the royals.
So it seems strange now to think about how little protection he had when he spent one month each year in Ireland, close to the border with the north in an area where the IRA often took refuge.
Odder still to think that, though the police kept an eye on his Classiebawn Castle, nobody watched Shadow V, the boat he had berthed at the Mullaghmore public dock.
The 79-year-old and others had set off on the boat about 11.30 on the morning of August 27 1979 when it was “blown to smithereens”.
Although he was pulled from the water, Lord Mountbatten’s legs had been almost severed and he died shortly after.
Also on the boat were one of his twin grandsons, 14-year-old Nicholas, and a local boat boy, 15-year-old Paul Maxwell.
Both boys also died, and within hours 18 soldiers, 16 from the Parachute Regiment, were killed by two booby-trap bombs near Warrenpoint.
An IRA statement said: “This operation is one of the discriminate ways we can bring to the attention of the English people the continuing occupation of our country.”
The Lord and his family had spent their summers at the castle, in Country Sligo in the north-west of the Republic.
It’s been said that the previous year the IRA had tried to shoot Mountbatten onboard his boat, but bad weather made it impossible for a sniper.
In 1979, IRA member Thomas McMahon had got into the unguarded vessel during the night and attached a 50lb radio-controlled bomb.
They were just a few hundred yards from shore when it was detonated.
Mountbatten’s eldest daughter, Patricia, Lady Brabourne, and her husband John, Lord Brabourne, were also onboard, along with their twins, Nicholas and Timothy.
John’s mother, Doreen, Lady Brabourne, was there, too. Aged 83, she would die from her injuries the following day.
Admiral of the Fleet Louis Francis Albert Victor Nicholas Mountbatter, 1st Earl Mountbatten of Burma, had been a Royal Navy officer and statesman.
In an incredible career, he had been First Sea Lord from 1954 to 1959, the same position his father, Prince Louis of Battenberg, had 40 years before.
He then served as chief of the defence staff until 1965, which makes him the longest-serving professional head of the British Armed Forces.
He was chairman of the NATO military committee for a year.
Lord Mountbatten was given a full state funeral, and is still fondly remembered.