The breakthrough came when I realised that all their names had been hidden within public service staff lists, scattered through pages and pages of military staff. Because hardly anyone knew even of the organisation's existence, they presumably thought the names would never be noticed. Comparing this list to other public service lists gave me general job titles for all these people. Combined with some early leaks, I was gradually able to construct the entire top-secret organisational plan from relatively open sources. The job then began of identifying people in the various sections willing to talk.
People have varied reasons for deciding to leak information.
There is, for instance, simply the relief of talking to someone who knows about their work after years of never being able to tell even their wives or husbands what they have done at work all day. But the main reason in this case was the officers' concerns that an important area of government activity had been too secret for too long, both from the public and Parliament. Some people felt strongly about intelligence activities they regarded as immoral or not in the country's interests. I decided who might be willing to talk to me, seeking people from all the various compartmentalised sections I wanted to study, and then quietly approached them. I am still surprised that most of the people I approached were prepared to talk to me, resulting in hundreds of pages of interview notes about the high-tech spy systems they operate.