A compelling new book reveals the composure and determination of Prime Minister Margaret Thatcher and her colleagues in the wake of the IRA's 1984 bid to wipe out her Cabinet at the Grand Hotel in Brighton.
The bomb - planted by Provo Patrick Magee - exploded just before 3am. It detonated in a bathroom one floor above the Prime Minister's suite, having been left there by Magee the previous month.
The blast tore a hole in the front wall of the Victorian hotel - but it remained standing.
Five people died, including Conservative MP Sir Anthony Berry.
A total of 31 others were injured, including the wife of Norman Tebbit, who was at that time the Trade and Industry Secretary.
Writing in yesterday's Mail On Sunday, author Steven Ramsey recounted how Mr Tebbit - now Lord Tebbit - had lain trapped in the rubble of the hotel, waiting to be rescued.
"We could hear water running and didn't know if it was rising about us.
"I suffered a couple of electric shocks, when rescuers cut through a cable which was still live.
"That was a moment when I thought I was dying..."
Margaret Tebbit was severely injured in the no-warning attack, and was left paralysed.
The book tells the heroic story of the rescue teams and medical staff who worked tirelessly to save the lives of the victims of the bombing, which made headlines around the world.
But it was the determination of the Prime Minister to keep calm and carry on that made the greatest impression.
Despite the carnage in the Grand Hotel, Mrs Thatcher was adamant that the Conservative Party conference - which was being held a few yards away at the Brighton Conference centre - should reconvene at 9.30am as scheduled.
"This is our opportunity to show that terrorism can't defeat democracy.
"It's what the victims would have wanted," Mrs Thatcher insisted.
And it was done.
Although police had advised Mrs Thatcher to enter the conference venue by a rear entrance, she refused, and went into the conference centre through the front door in order to "show the world that it was business as usual", the author writes.
In her conference speech that day, just a few hours after some of her friends and colleagues had been murdered and others lay seriously injured in hospital, the Prime Minister described the bombing as "an attempt to cripple Her Majesty's democratically elected Government".
"That is the scale of the of the outrage in which we have all shared, and the fact we are gathered here now - shocked, but composed and determined - is a sign not only that this attack has failed, but that all attempts to destroy democracy will fail."
Something Has Gone Wrong: Dealing With The Brighton Bomb by Steven Ramsey is published on January 11, priced £12.99