Heroin is now more widespread than cannabis inside prisons in England and Wales, according to the results of an official random drug testing programme.
Ministry of Justice data published yesterday shows that at two prisons - Erlestoke in Wiltshire and Featherstone in Wolverhampton - 16% of inmates tested positive for heroin. Across 101 prisons, 4.2% of inmates tested positive for heroin and 4% for cannabis.
The survey, carried out between February and April last year, was commissioned because of increasing concern about the growing misuse of a heroin substitute called Subutex - a prescription drug used in drug treatment programmes.
It confirmed claims that the use of Subutex - also known as buprenorphine - had spread "like wildfire" across the prison estate. Prisoners tested positive for Subutex use in 87 out of 139 jails - 50 of which had found no trace of the drug in previous drug testing programmes.
The Prison Service was also alarmed to find that in 11 prisons Subutex had overtaken heroin and cannabis as the most misused drug - many of them in the north-east, Yorkshire and Humberside areas. At Holme House prison on Teesside more than 20% of inmates tested positive for the drug. "The misuse of buprenorphine had grown to be a more significant problem," concluded the report, which was commissioned by the National Offender Management Service.
The justice minister, David Hanson, said yesterday the results justified the introduction of mandatory drug testing for the opiate substitute across all prisons from next month. "Prisoners will also be reminded of the drug treatment options available in prisons."
He said the random drug testing programme had shown that drug abuse inside jails in England and Wales had fallen from 24.4% of inmates testing positive in 1997 to 8.8% last year.
The decision to extend the programme of mandatory drug testing follows the announcement on Monday that David Blakey, former president of the Association of Chief Police Officers and chief constable of West Mercia, is to head an inquiry into the illicit supply of drugs into prisons.
The evidence of heroin abuse follows claims over the years that drug tests provide a perverse incentive for class A drug abuse because the active ingredients of cannabis remain in the bloodstream for much longer than opiates.
The Prison Service points out that on average 55% of inmates are problem drug users and some prisons report up to 80% of new inmates testing positive for class A drugs on reception. Governors argue that given this high level of abuse among new prisoners it is not surprising to see such a high demand for drugs in prison.