THOUSANDS of recovering heroin addicts should not be "parked" on methadone but should get the support they need to break their dependency, Iain Duncan Smith has said.

The Work and Pensions Secretary also insisted the Government's official drug advisers were "providing cover for perpetual drug addiction" in the UK by not suggesting a time cap on heroin users' access to substitute treatment such as methadone.

The Advisory Council on the Misuse of Drugs said earlier this month that a cap would increase the chances of a relapse, the spread of HIV and a surge in crime.

But Mr Duncan Smith said the council should take into account the harm done to individuals "parked on methadone indefinitely", as he advocated an approach to rehabilitation that fights "vested interests".

In a newspaper article yesterday, he said the evidence shows the policy of using methadone as a substitute to heroin has "failed".

Mr Duncan Smith, who founded the Centre for Social Justice think-tank, wrote: "Half of patients report using heroin on top of methadone regularly or sometimes, and nearly a third say they have sold, swapped or given their medication to someone else.

"Nor have those parked on methadone got the support they need, with 40 per cent failing to receive psychosocial counselling alongside their prescription."