This is all covered in _great_ detail in "The Defence of the Realm: The Authorized History of MI5", by Christopher Anderw: https://en.wikipedia.org/wiki/The_Def

This is all covered in _great_ detail in "The Defence of the Realm: The Authorized History of MI5", by Christopher Anderw: https://en.wikipedia.org/wiki/The_Defence_of_the_Realm https://en.wikipedia.org/wiki/The_Defence_of_the_Realm - this article is a nice summary of that book. The book goes into _lots_ more detail, including the CIA/Angleton side of all this.