Staff at Lincoln Prison intercepted a 29-page letter which had been soaked in the drug known as Spice.
Using a second hand Rapiscanner security device, staff at the prison found each page of the fake legal letter to be saturated in the drug.
The 29-page ‘document’ was soaked in plain NPS (new psychoactive substance) – aka Spice.
Prison staff said each A4 sheet had a current value within the prison of between £100 and £160.
The Ministry of Defence said the incident took place on August 18. All mail received at the prison is now being put through a thorough checking system.
The Independent Monitoring board has flagged up concerns in previous years about mounting cases of drugs being smuggled into UK prisons via ‘soaking’ methods.
In many cases spice, a former legal high, is sprayed into the paper or clothing where it dissolves. It’s then smoked as joints.
In the 12 months leading up to March 2018, just over 400 random mandatory drugs tests were carried out at Lincoln Prison. Of those that were not refused or flawed, some 113 tests were positive.
Of these, 61% showed as being under the influence of psychoactive substances, making this type of drug the most commonly used by a high majority in the sample.