Dr Paul Federoof and Steve Image Credit: Youtube/ Visionw2

A man has undergone chemical castration voluntarily after being terrified by his own fantasies of raping and killing women.

Steve (name changed) first started fantasising about extreme methods of sex when he was in his early twenties.

Joining the 18 April edition of Scottish Television Network's show This Morning's Crime Week, Dr Paul Federoof from Canada, an expert in sexual behaviour, discussed Steve's condition with show hosts Holly Willoughby and Philip Schofield.

Steve underwent the procedure after reaching a point where he started seeking out women as he drove around in his car, and even once planned a "perfect crime."

His plan never became reality, but he decided to seek help from Dr Fedoroff who suggested chemical castration to decrease his sex drive.

"It started with me cheating on my then-partner, this led to me looking online to meet people and everything progressed from there," Steve said, disguising himself with a hooded jacket.

"The sex became more boring over time so I started looking for more extreme methods. I enjoyed the challenge of meeting someone online and seeing how fast I could get them in to bed," he continued.

However, Steve's desires did not stop there and he started getting ideas of being violent towards his partners.

"It progressed to being more violent and then the fantasies of sexual assault and rape started ... and then I thought of killing the women I was sleeping with," he said.

Describing one night when he found himself standing at the threshold of committing a heinous crime he said: "I went out that night to do it. I purchased specific tools and had them in the trunk of my car. I drove around and got an individual in to my car. It was easy, but I never harmed her."

According to therapists, what prevented Steve from committing a crime that night was the fact that he got into a conversation with the woman, and started to know her as a person.

"What I discovered with my therapist is that when it came to people that I knew I had no interest in assaulting or raping them. My girlfriend was never harmed," Steve said.

Steve, after being assessed as being "extremely dangerous" according to the standard phallometric test, then volunteered to undergo chemical castration while under Dr Feredoof's counseling, Mail Online reported.

He believed that ever since he underwent the procedure, he has more control over himself.

"The removal of my sex drive did occur quite rapidly and made me a lot more comfortable. I lost interest in acting out my thoughts, I had no sex for a year and a half," he said.

"It is certainly no quick fix, but almost every time we do this things turn out very well," Dr Federoff said.

Chemical castration is a medical treatment which decreases sex drive in men using hormones.

The treatment is already mandatory for child sex offenders in Poland, Russia and certain U.S. states, while campaigners in the UK are pushing to introduce the treatment for sex offenders, the report said.