An undercover police officer who ended up addicted to heroin is suing his former force after he was jailed for giving police-issued weapons to his drug dealer. Robert Carroll claims his downward spiral of addiction began after he was encouraged to inhale heroin smoke at police training college, according to the Daily Mail.

After that, he was highly successful at putting drug dealers behind bars, but was also becoming ever more addicted to heroin using his alter ego Lee Taylor. He says that Greater Manchester Police (GMP) encouraged him to familiarise himself with the drug, but by inhaling the smoke he became “basically high”.

Carroll now says he was let down by the force and felt unable to seek help when his addiction became out of control. He announced his legal case after being released from prison on license four months into a 14 month sentence for misconduct in public office.

He said: “I felt ill when I walked out of there. They encouraged us to smell the smoke. That was pretty much the start of my downfall. Ultimately, I had a breakdown. I’m angry, angry at GMP. Basically they let me down. When I joined they said it was a big family.

“Well, they walked away from a member of that family when he got into big trouble. What sort of family is that? I had a mental breakdown and instead of helping me they went after me. My career has been cut short. Some may argue it was my fault and say: “Why didn’t you get help?”

“When you are in a position like that and in that kind of job you are surrounded by bravado and everybody else seems to be coping. It’s so hard to seek help when you are not sure what you need help for.”

He claims he only pleaded guilty to the charges to protect his wife, who is still a GMP police officer. He maintains he rarely drank before joining the police and never took illegal drugs.

The case is likely to add to existing concerns that undercover police officers are put under too much pressure and not helped when things go wrong. It follows the case of Mark Kennedy, whose role it was to infiltrate left-wing groups but in the end most of his work was undone and he began to side with the groups he was supposed to be monitoring.

As previously reported in the media his actions may well lead to the overturning of convictions for large numbers of extremists.