PRISONERS are using writing paper soaked in chemicals to smuggle 'legal highs' into prison, causing disruption, violence and unpredictable behaviour, according to prisons inspectors.

Scotland's Chief Inspector of Prisons David Strang said staff and prisoners themselves were often unaware of what the substances were that inmates were taking, as the effects of different types of the drugs – known as Novel Psychoactive Substances (NPS) – are so varied.

In some cases, weaker prisoners are forced to act as 'tasters' by more dominant inmates, to check the effects of a chemical, he added. "There is anecdotal evidence that some times they will pick on weaker prisoners to try it out on them."

He was speaking as HM inspectorate of prisons for Scotland (HMIPS) published a report on HMP Shotts, Scotland's only prison excusively for those serving long sentences.

The report says NPSs are increasingly a problem at the prison, as they are in several other Scottish jails.

Describing it as a "growing concern" he said: "Prisoners and staff informed us that they were anxious about the unpredictable behaviour which the use of NPS led to, creating heightened concerns about personal safety and well-being. It should be noted that this is not an emerging issue solely within HMP Shotts."

Some of those who had taken an NPS behaved in bizarre or violent ways, he said, but did not later remember it happening, even when shown themselves on CCTV.

He added: "There are so many chemical compounds, there is no test for them, so it is not easy to know how prevalent they are, but there needs to be better intelligence and more of a strategy for dealing with them and stopping them getting into the prison."

He also called for more education to make prisoners aware of the dangers of the substances.

In a largely positive report about HMP Shotts, Mr Strang said there were good relations between staff and the 531 prisoners, 60 per cent of whom are serving sentences of 10 years or more, including life sentences.

However the prison's unique role made it concerning that there is little support for those being liberated directlyy from HMP Shotts, the report says.

"Given that these prisoners had served sentences of many years, the lack of direct post-release support was particularly marked."

Mr Strang said long sentences in particular could leave prisoners institutionalised and out of touch with modern technology and other social developments. The Scottish Prison Serviced (SPS) should work more closely with councils and charities to ensure support was available to help former inmates adjust to life on the outside, he said.

The report also raises concerns about the impact of a change to the provision of education in prisons, which had led to staff shortages and meant among other things that prisoners have access to just one maths class a week. Meanwhile the prison library currently has no librarian.

"Staff concerns and uncertainties about their employment terms had impacted significantly on the staffing complement and resources for the delivery of classes," Mr Strang said. As a result, prison and education inspectors will reinspect HMP Shotts in the New Year.

A spokeswoman for the Scottish Prison Service said it was working with the Scottish Government and others to respond to the challenges of new drugs in jails.

"The SPS has been proactively managing New Psychoactive Substances (NPS) and its impact through awareness sessions and training to a wide range of staff and prisoners," she said. "A national training programme is currently being rolled out. While we are aware that there are issues with substance abuse within our establishments, there is no clear evidence to link this to Novel Psychoactive Substances."

The prison service takes substance misuse very seriously, she added. "

A comprehensive range of robust security measures are in place to prevent the introduction of contraband into our prisons. Significant investment continues to be made in the development of new technology and staff training to detect, deter and reduce the availability and supply of illegal drugs. Anyone found in possession of contraband is reported to the appropriate authorities.

"A range of substance misuse treatment and support services are offered to all those entering our care."