Although most of the current Sinn Fein leadership rose through the ranks of the IRA through the Seventies and Eighties, they were clearly uncomfortable with the IRA aspect of the series and said they would have to take advice. We pointed out to Sinn Fein that we did propose to cover the evolution of the Provisional IRA as well as Sinn Fein, since not to do so would be a travesty of history. In the course of our many discussions with senior Sinn Fein officials, there were frequent references to the need to consult the “leadership” and, occasionally, the mysterious “authorities”, without putting names or faces to either If the “leadership” says yes, things happen If it says no, they do not. I read modern history at Lady Margaret Hall, Oxford, from 1981 to 1984, and was going to be a teacher – teaching seemed like one of those things you do if you’re reading modern history. He’s a large man with closely cropped hair and with his bright yellow shirt, blue oval specs and slightly edgy Jack Dee delivery, he looks and sounds more like a minder than one of the top creative directors in the business.”Advertising isn’t about creating works of art to return to and discuss; it’s about making an immediate emotional impact,” he says, clicking his fingers to emphasise the point.

He gave a memorable interview.When I’d embarked on work on this series of programmes, colleagues had said there’d be no problem, as the Provisionals would love the publicity But I knew it wasn’t like that. Gradually, Billy was prepared to talk about his remarkable life in the IRA. After several weeks, the critical moment arrived when the question of an on-camera interview was raised It’s always the moment of truth Billy said he’d think about it, and finally agreed. It takes months or even years to build up the trust and the relationships on which real insights eventually depend. In the course of the year, my producer and I met him many times and spent hours listening and talking, fortified by endless ham sandwiches.

He’d told me that blowing up the Houses of Parliament wouldn’t have bothered him. Historically, Billy was the link with the IRA’s past and its present I’d interviewed him 20 years earlier and not seen him since. Under the circumstances, I thought it inconceivable that it was the IRA. I then drove to Derry, late as ever, to meet Provisionals there whose co-operation had been critical. They, too, have long indexes in the book.Then it was the 70-mile drive to Belfast to see the IRA veteran Billy McKee, who has 17 listings in the index. Billy, who looks like your favourite grandfather, was one of the founders of the Provisional IRA, the first commander of the Belfast Brigade, and a member of the IRA’s Army Council. As I stood outside in the rain, watching bored TV crews waiting for the next crumb from inside, a huge bomb went off in Markethill.