Dillon moved in. 'Bombs aren't just bombs, they are tactical weapons, used to achieve maximum results. You must make sure that an ambush is not just an ambush, but a total disaster for the enemy. And to achieve that, you need instruction from an expert.'

'What are you saying?'

'Let me tell you a story,' Ferguson said. 'It's from thirty years ago, when I was a Major in the Grenadier Guards, on my third tour in Ulster, seconded to staff at headquarters in Belfast. I'm not wasting your time, believe me.'

'Then proceed, General,' the President told him, and Ferguson began.

'August the twenty-seventh, Nineteen seventy-nine.' Ferguson took a deep breath, as if pulling himself together. 'I'll never forget that date because it was one of the worst days in my life. I was in the Incident Room at the Grand Central in Belfast when we received some truly dreadful news.'

'Which was?' the President enquired.

'The Queen's cousin, Lord Louis Mountbatten, liked to enjoy his family holidays in Ireland, despite the obvious security risks. That year, a radio-controlled bomb blew his thirty-foot fishing boat apart, killing Mountbatten, his grandson, his daughter's mother-in-law and a young boat boy.'

'Dear God,' the President said. 'I remember reading about it.'

'God had nothing to do with it, but the Provisional IRA did. The media went berserk. At the Incident Room, we were besieged, calls from all over the world. Then later that same day, just when I thought it was beginning to calm down, it got worse. Warrenpoint. Two trucks loaded with paratroopers were on their way to a market town called Newry when a huge roadside bomb hidden in a farm trailer was activated by a radio signal. Six paratroopers were killed and others wounded. The survivors took refuge in the ruins of a lodge at a place called Narrow Water. They radioed in for help and came under sniper fire. A Wessex helicopter carrying soldiers from the Queen's Own Highlanders landed close by. As they disembarked, another large bomb exploded, killing twelve soldiers, including their commanding officer and wounding others.'