It's not often we have a real-life spy as our special guest on LAD - but  tonight, stepping out of the shadows and into our spotlight is special guest  Major David Thorp - a man who has spent his entire life in signals  intelligence (SIGINT)... from the Cold War to the Falklands, and everything  in-between.

SIGINT is one of the least-known but most important aspects of battlefield  and peacetime intelligence gathering.  David's book, The  Silent Listener - Falklands 1982: The Inside Story of British Electronic  Surveillance and Intel Controversies, ignited a firestorm of controversy  when it was published... and tonight we get our teeth into his insider's  revelations about the sinking of the Belgrano and much more besides.