Around 100 paedophiles have been chemically castrated under a British government programme, a media report said on Tuesday.
According to the Daily Mail, the sex offenders volunteered to take the drugs designed to lower their libido in a pilot experiment at the prison in Whatton, Nottinghamshire.
A single course of the leuprorelin drug reduce testosterone levels to that of a pre-pubescent boy.
Chemical castration involves a man taking hormones which suppress the production of testosterone, leading to a decreased sex drive.
Poland introduced mandatory chemical castration for sex offenders in 2009 and Russia recently introduced similar legislation. It was introduced in South Korea in September last year.
Germany and the Czech Republic, however, reportedly use voluntary surgical castration to treat sex offenders.
The ongoing experiment at the Whatton prison, a special jail that holds male sex offenders, is being run by the Prison Service and the department of health.
"I have referred around 100 people for treatment. We know the treatment works to reduce sexual arousal and fantasies," said programme coordinator and criminal psychiatrist Don Grubin.
The experiment has brought out differing opinions.
Psychologist Ludwig Lowenstein backed chemical castration, saying a child's right to protection was more important than the freedom of paedophiles.
But Juliet Lyon, director of the Prison Reform Trust, said: "It's difficult to see why anyone would invest public money in controversial medication when you could fund sex offender treatment in prison, police and public protection on release, all of which are proven to reduce reoffending."