More must be done to stop the "postcode lottery" of provision for drug-addicted persistent offenders after prison, a think tank has said.
Offenders fear they will resume drug use back in the community
A massive expansion in residential centres is needed, the Re-thinking Crime and Punishment group believes.
Money for treatment centres should be ring-fenced to stop local authorities spending it on other services, it said.
The group thinks residential care for addicts on leaving prison could stop them falling back into their habit.
A record amount is being spent on drug treatment, with Department of Health and Home Office rehabilitation funding at £573m for 2004-5.
But addicts in some parts of England still have to wait eight months for access to residential schemes, BBC home affairs correspondent, Danny Shaw reports.
The delays deter problem drug users from seeking help and undermine attempts to cut crime, the Re-thinking Crime campaign said.
It advocates local authorities funding drug treatment specifically - at present the money comes out of their community care budgets.
A residential treatment centre in Wiltshire, called Clouds, said that for three months in 2003 it was unable to fill all its places in spite of long waiting lists.
One explanation was that some of the money may have been diverted into other services towards the end of the financial year, centre director Nick Barton, said.
Former drug addict Steve, from Basildon, Essex, is serving two years for ram-raiding a shop - he has had more than a dozen custodial sentences.
He refused to go onto a prison wing where he knew there were drugs available and was put into the segregation unit.
He wants to go into rehab outside prison so he is supported full time.
"Everyone I know uses drugs of some sort, so it's going to be hard," he said.
"I want my life back in order.
"There've been times where I've committed a crime just to come into prison to get off the drugs, and when it's time to go out of the gate, I've not wanted to go."
His prison case worker, Rebecca Saunders, said it is "incredibly frustrating" that there is no funding available to secure residential care on release.
"You're dealing with someone's life, with his hopes and dreams and his desire to move forward," she said.
"And basically you're saying we don't have the money to invest in you.
"I find it quite shattering, - someone like Steven, at that stage when he is ready to change, he would do really well in the right environment."
The National Treatment Agency said most drug-using offenders did not need residential rehabilitation but it should be available for those who do.
The health authority denied it was a widespread problem but admitted aftercare was crucial and said improvements in supporting addicts have been made.