Katherine Gun broke the Official Secrets Act. She should have been tried in court, and she should have gone to prison. Her case was the very definition of open-and-shut. This book spends much of its time trying to persuade the reader that she was, in fact, a noble and courageous whistleblower, and who was trying to do the right thing. What it is, in reality, is a bit confused.
Where this book is strong is its exposition of events leading up to, and around, the Iraq war. It offers a very good and detailed look at the road to war, the decisions that were taken, by whom, and when. Reading this, there is no question that, as an absolute minimum, Blair and Bush lied to their respective countries and parliaments, and a reasonable case can be made against both that they are guilty of war crimes. This, of course, will never come to pass. However, it is also circular, and repetitive, and keeps saying the same things as it tries to make its point, both literally and metaphorically.
It also uses the benefit of hindsight to make its defence for Gun's actions. She made her decision to commit treason because of a moral viewpoint regarding one aspect of her role; the repeated assertions that follow imply that she knew all the other details that are now available, and was making her decision because of that. Of course, this isn't - cannot be - the case, so it loses some of its efficacy in the telling.
But, whilst I don't agree with some of the arguments, they are both objective and fairly compelling, and there are certainly some elements that give pause for thought. Mostly, though, it simply reveals someone who was either staggeringly naive or willfully malicious. On balance, I am inclined to go with the former, but a small part of me still wonders.