250,000 people disappear in the UK every year. 99% are found within the first year. But what about the remaining 1%? How are they still missing – and why did they disappear in the first place? This week, Tim Weaver meets with Dr Nigel Blackwood, forensic psychiatrist, and Frank M. Ahearn, author of 'How to Disappear’ - a professional that helps people vanish for a living. Using their expertise, Tim explores the complex reasons why people might choose to leave their life behind, and why that decisive step is even more difficult than you think.