The Brighton bombing is a magnet for alternative histories, sliding doors theories in which it is possible to enter a world of infinite speculation about what might have followed had the most consequential British politician of her time been murdered that night. It was, as ever, the easily forgotten people, those whose lives were obliterated or shattered, who were sacrificed for this nothingness. Less than three months later IRA bombs targeting Falklands veterans killed 11 soldiers in London’s Hyde Park and Regent’s Park on the same day. Just two minutes before the bomb went off, its primary target, Margaret Thatcher, emerged from the bathroom of the Napoleon suite on the first floor to continue working on various government documents that required her attention.

In Carroll’s telling, culled from multiple sources and interviews, the devil is very much in the detail. The bomb also fractured irreparably the bond between Thatcher and her closest cabinet colleague (and, at the time, most likely successor), Norman Tebbitt. The assassinations shortly before and after the 1979 general election of Airey Neave, probably her closest political friend, and of the war hero and British royal family relative Lord Mountbatten forced her to address for the first time the decade-old Northern Ireland ‘Troubles’.

Mrs Thatcher was still fully dressed and polishing her speech for the final day of the Conservative Party conference when the bomb exploded five floors above her at 2. Rejoice” declaimed Margaret Thatcher outside No 10 Downing Street, London, on April 25th, 1982, in her first media doorstep after British forces had triumphed in the 74-day Falklands War that had cost more than 900 lives. An exciting narrative that blends true crime with political history, this is the first major book to investigate the Brighton attack. Biography: Rory Carroll, currently the Guardian's chief Ireland correspondent, was a 12-year-old living in Dublin at the time and remembers the scenes in the aftermath of the Brighton bombing. Moreover, on the advice of a sympathetic engineer who studied the hotel, the bomb was placed so as to bring the chimney stack down on those below, effectively using the building itself as the real weapon.

She even changed her speech to tone down attacks on Neil Kinnock and the Labour party, cutting references to the “enemy within” and making her seem, if anything, more serene than usual. It was 1984, the fifteenth year of the Troubles, and London seemed to have endless bomb scares (and bombs, some of which are covered in detail here) during that period. Photograph: Larry Ellis/Getty Images View image in fullscreen Margaret Thatcher and her husband, Denis, at the Conservative conference in Brighton, the morning after the bombing of the Grand hotel.The author then goes back, looking at the history of the Troubles and other assassinations, including that of Lord Mountbatten in 1979, and Airey Neave the same year. He checked in as Roy Walsh, later insisting he was unaware that it was the name of another IRA volunteer who had carried out a bombing in London in 1973, and paid in cash for a three-night stay in room 629, which afforded him an expansive view of the promenade and the sea. British prime minister Margaret Thatcher looking pensive at the Conservative Party Conference in Blackpool. Her very first comments were to apologise for being Irish and advising me if this was upsetting me, she would get one of her colleagues to do the work,” McClean said.

Margaret Thatcher was the perfect opponent for the Provisional IRA, as implacable in her belief that right was on her side as they were in theirs. It toppled through the blast hole, then veered sideways and plunged down a vertical stack of rooms with numbers ending in 8.In this fascinating and compelling book, veteran journalist Rory Carroll retraces the road to the infamous Brighton bombing in 1984 an incident that shaped the political landscape in the UK for decades to come. Today we were unlucky, but remember we have only to be lucky once, you will have to be lucky always.