Investigative journalist John Sweeney is known for what he calls his "explosive" documentaries at BBC Panorama. In this intimate interview, he says what it was like to be harassed by the Church of Scientology; explains how he challenged the evidence of Professor Roy Meadow to help free cot death mum Sally Clark and six others, and recounts the challenges of going undercover in war zones like Chechnya, Zimbabwe and North Korea. 0.55 - Covering the Paris attacks