Scottish prison chiefs are to scrap the compulsory drug testing of inmates after admitting it had failed to tackle rising heroin abuse behind bars.
Prison officers say mandatory random drug tests (MRDTs), which were introduced ten years ago at the height of the so-called "war on drugs", have actually encouraged the use of heroin in jails.
But opposition politicians say the decision shows the Scottish Executive has "thrown in the towel" on eradicating drugs in prisons.
Under current rules at least 10 per cent of prisoners are tested every month. If an inmate tests positive, privileges, including access to their money, recreational activities and movement between jails, can be stopped.
Under the proposed new system, there will be no such punishments. Instead, officers will concentrate their efforts on encouraging prisoners to seek treatment for their drug problems.
Scrapping MRDTs is expected to be formally agreed later this year, but it is understood prison chiefs have already decided it is a necessary step. The Executive has given its blessing to the move.
According to research, about half of prisoners will have taken drugs in jail in the previous month. Of those, nearly a third will have taken heroin.
A senior prison source said: "The existing approach to tackling drugs in prison simply isn't working. People are continuing to use drugs. In fact, it pushed people on to other drugs which do not stay in someone's system for so long - like heroin, which only stays in the urine for three days. Often, people who are taking drugs were 'getting off' because the tests were coming back negative.
"Mandatory testing only really works if people are willing to be treated, but if they aren't then it isn't much use."
However, Annabel Goldie, the Tories' justice spokeswoman, said: "This is yet another indication that the Scottish Executive has thrown in the towel in the fight against drugs. When so many of our prisoners are known to be drug addicts, it is essential for both prison regimes and any meaningful attempt to assist prisoner rehabilitation that we know what's going on in our prisons.
"This is a significant step backwards and yet further evidence that the Scottish Executive has given up on drug abuse in Scotland."
A survey last year revealed that random drug tests had had "no effect" on more than three-quarters of prisoners.
In 2003-4, nearly 6,500 mandatory tests - one for each prisoner - were carried out, revealing 32 per cent of inmates were taking heroin. About a fifth showed signs of cannabis abuse.
Previously, the proportion of inmates taking heroin had remained relatively constant at about a quarter.
Lord Forsyth, who as Scottish Secretary, introduced MRDTs to jails north of the Border in 1994, claimed the decision to abandon them showed the prison system had "failed lamentably" to tackle drug abuse.
"This is a disaster for people who have to go into prison because people who go in without a drug problem very often come out with one," he said.
"If you look at the causes of crime, drugs play a very important role, causing much re-offending, particularly in relation to robberies and assaults.
"Prisons are supposed to be about protecting the public. They are not doing that if they are discharging people with drug problems.
"To abandon [MRDT] because it hasn't worked is basically to acknowledge they have failed lamentably to address drug taking in prison."
But Sir Clive Fairweather, a former chief inspector of prisons, accused Lord Forsyth of having forced mandatory drug testing on prisons when they did not have proper drug treatment programmes in place.
"Michael Forsyth asked me what I thought about random drug testing," he said. "I felt the educational and rehabilitation programmes weren't in place, but he said he was going to press ahead with them anyway. He introduced them with astonishing speed.
"The Scottish Prison Service did their best to implement what was a political decision."
He went on: "The drug problem is getting so huge, it would make more sense to test people to find out who hadn't taken drugs.
"I think it's a bold move by the prison service, although the public may not like it. It makes sense to transfer resources from the punitive, mandatory approach and concentrate on working with prisoners to help them overcome their problems."
A significant chunk of the prison service's £4.4million addiction-problems budget is spent on MRDTs. About 7,000 testing kits have to be bought and analysed every year, and frontline officers have to spend a large amount of time carrying out the tests.
More funds will in future be diverted towards rehabilitation programmes in an attempt to drastically reduce the number of prisoners being released with an addiction problem.
Initially, prisoners who tested positive had their sentences increased, but that was scrapped after a challenge under human rights laws.
Tom Wood, the chairman of the Edinburgh action team on alcohol and drugs and a former deputy chief constable of Lothian and Borders Police, said there was an "immense" drugs problem in prisons. "Sometimes we have to be bold and change tactics," he said. "We have got to try something new because the systems that have been tried up to now aren't working.
"This is a radical move and people will say it's throwing in the towel, but I'm supportive of anything that gets to grips with the problem."
Prison officers say moving away from mandatory testing will create a less confrontational approach by staff towards inmates, encouraging more to take part in drug treatment programmes.
Eighty per cent of inmates who admit injecting heroin say they share needles, raising the spectre of an HIV and hepatitis epidemic in Scottish prisons.
Professor Sheila Bird, who introduced HIV tests for prisoners at Saughton prison in Edinburgh in 1991, said mandatory tests had failed to show how many prisoners were injecting heroin. "MRDTs don't give you enough information about how drugs are taken," she said. "Why spend the money on having trained officers dealing with mandatory tests when all you get is a headline figure?"
A spokesman for the Scottish Prison Service said: "The SPS believe encouraging prisoners to face up to their problems at an earlier stage is central to a modern, mature approach to tackling drugs in prison. For many prisoners, this is a very tough decision. When they do, they can expect support from SPS."
LATEST DEATH ADDS TO GRIM FIGURES
THE latest drug overdose in a Scottish prison took place last weekend when a young woman was found dead at Scotland's only all-female prison.
The woman's cell-mate was also rushed to hospital after using a batch of what is believed to have been contaminated heroin smuggled into the prison.
Lynn Ann McLean, 21, of Kelso, was on remand at Cornton Vale Prison in Stirling when she was found dead in her cell on Sunday morning.
At one point recently, 100 per cent of admissions were found to have addiction problems.
The latest death highlighted the troubled history of Cornton Vale, where five women committed suicide in the late 1990s. An average of one suicide a year has taken place since 2000.
A BBC investigation into Kilmarnock prison last month claimed officers turned a blind eye to drug-taking.
Last year prison staff recorded 3,011 offences of taking or concealing drugs. More than 300 prisoners were caught in the act of taking drugs.