Operation Stopwatch/Gold, said CIA chief Alan Dulles, was one of the most valuable
and daring projects ever undertaken. In 1955 it ran a tunnel 800 metres under the
Russian sector of Cold War Berlin, and for more than a year tuned into Red Army intelligence.
This was an almost impossible trick: apart from the technical wizardry needed, any
noise or vibration could have given the game away.
That the operation succeeded is even more surprising than it looks. Trust, even between
allies, was dangerous. Despite the Burgess and Maclean affair, the Americans had
decided that co