BBC Security Correspondent Gordon Corera goes inside the world of GCHQ to hear the legacy of Alan Turing on today's codebreakers

Alan Turing was the British mathematician who broke German codes at Bletchley Park during World War II. He committed suicide after he was prosecuted for homosexuality. A new biography is being published of Turing's life ­ by his own nephew Dermot Turing. It was launched yesterday in ­GCHQ. Gordon Corera is the BBC’s Security Correspondent.