I had to lie to do my job, to stay alive, but when you become an expert at deceiving the people you love, how can you trust yourself?

'John' is the UK's most successful undercover police operative, who took on cases no one else would. Invisible to you or I, 'John' worked in the most extreme circumstances, taking down drug gangs, murderers, firearms dealers and even serial killers.

In a twenty-year career, amid staggering deep cover operations, 'John' has taken on countless identities, while also juggling being a husband and dad to his family waiting at home.

'John' put his life on the line every day to see justice served and to make his country safe. This is his incredible true story.