A spike in violence linked to the supply of synthetic cannabis drug Spice has been recorded at a prison for inmates who are preparing to be released into society, inspectors have found.
Resettlement prison HMP Blantyre House, in Kent, has seen an increase in the number of violent incidents, including two serious assaults, HM Inspectorate of Prisons (HMIP) said following an unannounced inspection.
Spice, a former legal high banned in 2009, and its associated debt and bullying, was blamed in part for the rise in violence at the 120-capacity jail, which was described as "one of the jewels in the Prison Service crown" following a 2010 inspection.
Prisoners told inspectors a gang was involved in the use of Spice, which recreates the effects of cannabis, such as relaxation but also paranoia, who had been intimidating more vulnerable inmates and new arrivals.
Current testing methods do not detect Spice, so the low positive drug testing rate did not give an accurate picture of the availability of drugs in the prison, HMIP added.
Andrew Neilson, director of campaigns at the Howard League for Penal Reform, said: "This is yet another report identifying that a prison which was once excellent is now floundering because of budget cuts.
"Violence and bullying, apparently linked to Spice, is being seen in a prison which only four years ago was described by inspectors as 'one of the jewels in the Prison Service crown'.
"It shows the disastrous consequences that happen when the prison estate becomes focused on warehousing people rather than turning lives around."
Class-B drug Spice is a synthetic cannabinoid - a chemical made to act like THC, the active part of cannabis, which is usually sold in herbal smoking mixtures.
Regular use of products containing synthetic cannabinoids may increase the risk of later developing psychotic illnesses including schizophrenia, according to drug advice website Frank.
A considerable body of anecdotal evidence from staff and prisoners revealed that synthetic cannabinoids, such as Spice, were easily available and causing a number of problems, including debt, bullying and intoxication, the inspectors said.
Testing methods to detect Spice meant evidence was limited to actual finds, of which there had been three in the six months to August 2013, HMIP added.
Inspectors recommended the prison should have a "multidisciplinary approach" to tackling substance misuse and an effective supply reduction policy.
Chief inspector of prisons Nick Hardwick said: " Blantyre House still retains many of the strengths we have identified in the past.
"In particular, its small size means there is an opportunity for its experienced staff to get to know prisoners well and address their needs and behaviour in a personalised way that is simply not possible in larger establishments.
"Those strengths should be advantages in dealing with the wider and more complex range of needs among the prisoners Blantyre House now holds - but neither the prison nor the wider prison service have yet got to grips with the changes required to meet these needs or the resources necessary to make them."
Michael Spurr, chief executive of the National Offender Management Service (Noms), the executive agency of the Ministry of Justice that runs offender services in the community and in custody, said: " I am pleased that the chief inspector has highlighted Blantyre House as a good resettlement prison with safe and productive conditions - this is a credit to the hard work of the governor and his staff.
"We recognise that the population at Blantyre House is more complex and challenging than previously and the governor and his team will continue to have the support needed to take forward the recommendations in the report."
A Prison Service spokesman said: " We take the misuse of drugs in prisons, and the problems they cause, very seriously.
"We work hard to keep contraband out of prisons and use a range of security measures, including random mandatory drug testing of prisoners and close working with the police and other agencies.
"We will always press for the most serious charges to be laid against anyone attempting to bring drugs and other contraband into prisons, and anyone caught dealing or bullying may be returned to closed conditions."