Giving a British drug addict cash incentives for sterilisation is "exploitative, ethically dubious and morally questionable", a leading drugs charity has declared.
DrugScope chief executive Martin Barnes spoke out after the 38-year-old addict, who wishes to be known only as John, was given £200 in exchange for a vasectomy.
John, who has been addicted to opiates for 15 years and has been involved with drugs since he was 11 or 12, said the cash incentive spurred him into going ahead with the procedure.
But Mr Barnes said: "It is a fundamental principle of the NHS constitution that all treatment should be both informed and consensual; we believe that offering cash incentives to often very poor and marginalised people in return for sterilisation runs directly counter to this. It is exploitative, ethically dubious and morally questionable."
He said the premise that people with drug problems should be sterilised "further entrenches the significant stigmatisation and demonisation experienced by this group, making it less likely that people will come forward for help and support when they need it most".
"And where should the line be drawn?" he asked.
"Potential parents experience a range of problems or circumstances which may present risks for the welfare of their babies and children. Who would be targeted next - people who smoke, have mental health problems, or live in poverty? Ensuring access to good quality treatment and welfare and safeguarding systems is the most effective, rational and humane approach to this complex issue, not sterilisation for cash."
Earlier, the addict, featured in BBC London's Inside Out programme on Monday evening, said: "It was kind of what spurred me into doing it in a way. It was something that I'd been thinking about for a long time and something that I'd already made my mind up that I wanted to do. Just hadn't got round to it."
John, who admitted he had stolen things in the past and dabbled in dealing drugs, said that he was going to spend the money on overdue rent and shopping.
The controversial American charity Project Prevention was set up by Barbara Harris from North Carolina, who adopted four children born of a crack addict mother. She watched the children struggle with the addiction passed on to them by their mother.