After 34 attempts to sink the Tirpitz it in its Norwegian lair, the RAF 617 'Dambusters' Sqdn and 9 Sqd succeeded. The bombers dropped nine 12,000lb 'Tallboy' bombs in 90 seconds.With eyewitness accounts from surviving RAF crew, one of the Luftwaffe fighter pilots, and German sailors who were on Tirpitz that day, this documentary tells this extraordinary story. Historian Patrick Bishop examines exactly how the German defences were breached including intriguing evidence of collusion.