On the 25th anniversary of the Good Friday Agreement, Peter Taylor tells for the first time the gripping story of Operation Chiffon, MI5's top-secret intelligence operation that finally helped bring peace to Ireland.

April 1998: the Good Friday Agreement is signed, ending decades of violence and bloodshed in Northern Ireland. The process of getting the IRA to end its so-called 'armed struggle' was always the prerequisite of the search for peace. It was Operation Chiffon that made it possible.

Operation Chiffon takes us inside the top-secret intelligence operation whose roots go back to the bloodiest years of the conflict in the early 1970s, involving officers from MI6 and, later in the 1990s, MI5. The remarkable story, which has remained hidden for forty years, is now revealed by legendary BBC journalist Peter Taylor with unique access to the officers involved. Drawing on exclusive interviews and Taylor's fifty years of covering the conflict, the book narrates in first-hand detail how those involved risked their careers - and their lives - to help secure the fragile peace that exists today.

Taylor vividly brings this covert operation to life and in the process chronicles the history of Sinn Féin, rising from obscurity in the early days of the Troubles to becoming the largest political party in Ireland today. It is a story fraught with uncertainty and danger that, as Brexit risks destabilising the peace that was achieved in the Good Friday Agreement 25 years ago, is more important to remember than ever.