John Sutherland was a high flier who joined the police in the early 1980s.

At the height of his career he was appointed borough commander in Southwark in London, with its share of murders and violence. He was also a trained hostage negotiator.

In 2013 he realised he could not cope anymore and has now written a memoir called Blue detailing his experience.

He spoke to our reporter Becky Milligan.

(Photo: John Sutherland. Credit: Zac Crawley)