A Staffordshire prison has the highest level of heroin abuse of any jail in the country.

New Ministry of Justice figures reveal that more than one in six (16.7 per cent) of inmates at Featherstone, near Wolverhampton, tested positive for the opiate in random tests – four times the national average.

Of 139  English and Welsh jails only 38 were clear of positive opiate tests. The same number were also free of cannabis in a three-month study done between February and April last year but published for the first time today.

In total, 4.2 per cent of all random drug tests found evidence of opiate abuse and four per cent of cannabis. 

HMP Prison Birmingham had a positive rate of 5.6 per cent, Dovegate Prison in Staffordshire, 8.6 per cent, and Stafford Prison one per cent.

Figures came as ministers announced that testing for the opiate substitute buprenorphine is to be introduced into all prisons next month. 

The survey also confirmed the use of buprenorphine, also known as Subutex, had spread “like wildfire” with positive results in 87 jails, 50 of which had no trace in previous testing programmes. 

Justice minister David Hanson said a review on disrupting drug supplies in jails is due to be complete by May. 

A Ministry of Justice spokesman said drug use in prison measured by the random mandatory drug tests showed the positive rate fell from 24.4 per cent in 1996/97 to 8.8 per cent in 2006/07.