Peter Taylor investigates what Britain is doing to counter the threat of violent extremism. In 2010, 140 million pounds will be spent to win the battle for the hearts and minds of young Muslims, but the policy risks alienating many in Britain's Muslim communities. With unique access to a man who came face to face with Al-Qa'idah and the inside story of how police managed to thwart would-be suicide bombers, the programme examines the biggest single threat to national security.