Drug addiction experts have reacted with horror at the revelation that a controversial American charity worker who pays addicts to be sterilised is setting up a franchise in Britain.

Project Prevention, which operates out of North Carolina, has stopped more than 3,500 drink and drug addicts from having children by paying them up to £200 to seek long term or permanent forms of contraception such as an IUD implant or full sterilisation. Once the addicts prove that an operation has been carried out they are awarded a cash sum which, even the charity admits, usually goes towards feeding their habits.

Barbara Harris, the charity's founder, believes encouraging drug addicts to seek sterilisation saves thousands of children from growing up within a damaged environment. She has adopted five children who were born to crack-addicted mothers. But critics say her approach automatically stigmatises all addicts as bad parents.

That argument has now crossed the Atlantic following the announcement that Mrs Harris has founded a freephone number for UK addicts who will be paid if they get themselves sterilised.

Andrew Horne, the director of Addaction, one of the UK's largest addiction charities, lambasted the American charity's approach yesterday.

"There is no place for Project Prevention in the UK because their practices are morally reprehensible and irrelevant," he said. "Our first-hand experience shows that people can make positive changes with the right support – both for themselves and for their children. In fact, many of our clients stopped using drugs because they became a parent."

Mrs Harris, who is currently in the UK, defended her work and claimed she was already talking to a number of unnamed drug agencies in London.

"We're going to make this offer to drug addicts, social workers, law enforcement," she said. "Anyone who comes in contact with these women can refer addicts to us now we have an 0800 number here in the UK. We hope the scheme will grow as much here as it did in the US, and that people will support us financially. We need the cash to pay the addicts."