A former police sergeant, dubbed Robocop for his arrest record, has left the force due to mental health issues.
Ali Livingstone had made 5,000 arrests in 15 years and said he would arrest up to 700 people in a single year during his career with Suffolk Police.
The 36-year-old said he had a "significant" mental breakdown in 2018.
He said that to help others, he wanted to be open about his post-traumatic stress disorder (PTSD), depression and anxiety, and is writing a book.
"I went from being the UK's top arresting officer to being so troubled by what I'd seen and done in the line of duty that I've had to walk away from the very job that defined me," he said.
Mr Livingstone, from Suffolk, joined the force at the age of 18 and by the age of 27 was Britian's most prolific officer for arrests ,averaging 2.2 every working day.
High profile cases he was involved in included the Steve Wright murders in 2006 and the shooting at Zest nightclub in Ipswich.
Mr Livingstone was working as a response sergeant tactical advisor, negotiator and police search adviser before his mental heath issues took hold.
He took two months off before he returned to work, but that only lasted two months. He went back again in the September but finished in December.
Mr Livingstone said there was not a single event which triggered his PTSD and Suffolk Police had been supportive.
He said he wanted to help others by raising awareness and sharing his experience.
Suffolk Police said it took duty of care to all of its employees "very seriously" and provides support for staff and officers living with PTSD, trauma and complex mental health issues.