Book Commentary: Battleground Berlin

Numerous authors have reported that our Berlin tunnel, from which we collected Soviet phone calls made from Germany from Spring 1955 to Spring 1956, was producing only information prepared for us by the KGB, as they had known of the tunnel long before it was dug. Their penetration of MI-6, George Blake, was the recorder of the meeting we held with the British to discuss the tunnel plan. In fact, as the KGB co-author of the book, who was aware of the KGB action to have the tunnel "discovered" without compromising Blake, stated that the KGB had tried to increase security in phone conversations on the cables running through the tunnel, but could not take action to alert users of the lines, or even KGB officers who were not cleared to know of the Blake operation. Therefore, the information which we acquired from the tunnel was actually reliable and valuable as generally concluded at the time.

Battleground Berlin, David E. Murphy, 1997

http://www.amazon.com/Battleground-Berlin-CIA-vs-Cold/dp/0300072333/