Book excerpt: When British and American forces invaded Iraq in April 2003, their intelligence operations got to work looking for the WMD their governments had promised us were there. They quickly realised no such weapons existed. Instead they become faced with an ever-increasing spiral of extremism and violence that was almost impossible to understand, let alone contain. This book tells the story of what happened next, one of the most dramatic and sustained operations in our recent military history. Up against the wall, under the aegis of the joint forces commanded by Major General McChrystal, our men moved into action using the wide variety of aircraft and weaponry at their disposal. Combining intelligence with brute force, the SAS went on the attack, night after night targeting Al-Qaeda and other insurgent groups with an intensity never before practiced by the service, destroying the terrorist threat and saving lives.