On 27 August 1979, Lord Mountbatten, great uncle to Prince Charles, was blown up at sea by the IRA off the coast of Mullaghmore, Sligo.
Three others were killed on the boat that day, including two teenage boys. The bomb was detonated via remote control by republicans watching from the shore.
That moment would lead to a collision between the Royal Family, the heart of the British establishment and Irish republicanism.
Later that afternoon, in a second strike, the IRA killed 18 British soldiers and one civilian during the Warrenpoint ambush in what was the biggest single loss that the British army experienced in Northern Ireland.
After the death of Mountbatten, the IRA issued a statement which said: "The IRA claim responsibility for the execution of Lord Louis Mountbatten. 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 death of Mountbatten and the tributes paid to him will be seen in sharp contrast to the apathy of the British Government and the English people to the deaths of over three hundred British soldiers, and the deaths of Irish men, women, and children at the hands of their forces."
On Thursday at 22.45 on BBC1, The Day Mountbatten Died will retell the events of that day.
The documentary previously aired to mark the 40th anniversary of the event and it features interviews with Lord Mountbatten’s granddaughter India Hicks, who was holidaying with her grandfather and family at Classiebawn Castle in Sligo that summer.
Mary Hornsey, who was on holiday in the area with her family at the time and whose 15-year-old son Paul Maxwell was one of the young people killed on board the boat, will also feature in the documentary.
Also interviewed in the film is Anthony McIntyre, a former member of the IRA, who was in prison at the time of the assassination and Kieran Conway, who gathered intelligence for the IRA.
At the time of its original release, Sam Collyns’s documentary received some very impressive reviews:
The Guardian - “Director Sam Collyns’s powerful film is a respectful masterpiece.”
Sunday Telegraph - “This excellent film examines the build-up and aftermath with measured contributions from all sides. The underlying message highlights what is at stake if the peace process is disrupted – as Brexit approaches the stakes could not be much higher.”
The Observer - “Produced by Alison Millar and Angus Macqueen, director Sam Collyns’s poignant exploration of the events surrounding the IRA’s assassination of Lord Louis Mountbatten in August 1979 is the product of documentary royalty.”
The Mail on Sunday - “This assured documentary provides a grimly compelling snapshot of a day that left a dark legacy that will never fade.”
The Telegraph - “Sam Collyns’s powerful commemoration of one of the darkest days of the Troubles…Essential viewing for our leaders.”
The Day Mountbatten Died airs at 22.45 on BBC One on Thursday, August 27.
Take a look at what's in store.
'The Day Mountbatten Died' tonight at 9pm on BBC One NI. pic.twitter.com/lex8CaWtxx
— BBC Northern Ireland (@BBCnireland) August 19, 2019