On October 12 1984, the Irish Republican Army tried to assassinate Prime Minister Margaret Thatcher and the entire British Cabinet - and they almost succeeded.
A bomb had been placed inside Brighton's Grand Hotel, where most leading Conservative Party members were staying during their annual Tory conference.
Five people were killed and 34 injured in the most devastating attack ever on British politicians.
Those who died included Sir Anthony Berry MP and Roberta Wakeham, wife of Parliamentary Treasury Secretary John Wakeham. Industry secretary Norman Tebbit was injured and his wife Margaret was left permanently paralysed.
Mrs Thatcher had been working in her suite when the 20lb gelignite bomb detonated at 2:53am on the last night of the party conference.
The explosion ripped through the top floors of the hotel, creating a huge hole in its front and causing a chimney stack to collapse and crash through the centre of the building.
It missed the Prime Minister's living room by inches, but caused damage in her bathroom - where she had been just two minutes before the bomb went off - and bedroom, where her husband Dennis was sleeping.
The following day, the IRA issued a statement taking responsibility for the bomb. It said: "Today, we were unlucky. But remember, we only have to be lucky once; you will have to be lucky always. Give Ireland peace and there will be no war."
Despite the chaos, the conference started on time. A defiant Mrs Thatcher took to the stage and addressed Tory Party members: "This government will not weaken. This nation will meet that challenge. Democracy will prevail."