Six Yorkshire prisons have been issued with specialist scanning equipment and detailed instructions on handling incoming mail following a surge in attempts to post drug-laced paper and other contraband to inmates.
Correspondence is being exploited to convey illicit substances and items into establishments, according to an official security briefing.
Instances have been reported in all prison regions in England and Wales, and in both the male and female estate.
Finds have included “large amounts” of drugs, tobacco and SIM cards, the document circulated by HM Prison and Probation Service says.
It also reveals that some jails have reported chemically laced paper containing household chemicals such as alloy wheel cleaner, insect poison, koi carp sedative and acetone.
As previously reported, this method has been used to smuggle the drug spice into HMP Leeds, where laced pieces of A4 paper are said to fetch as much as £1,000 each.
Prisons Minister Rory Stewart said scanners which can detect invisible traces of drugs soaked into clothing and paper have been installed at 10 of the most challenging jails.
The prisons, which include HMP Leeds and HMP Wealstun at Wetherby, were chosen in August for a £10m pilot to reduce levels of violence and drugs behind bars.
Four other Yorkshire prisons selected for the pilot have also received the kit – HMP Hull, HMP Humber in East Yorkshire, and HMP Lindholme and HMP Moorland in South Yorkshire.
Mr Stewart, who previously pledged to resign if the crackdown failed to make improvements, said that drugs in prison have been a “game-changer”, driving self-harm and extreme violence.
“As the methods used to smuggle drugs into prisons continue to evolve, our response to that threat becomes ever more agile and vigilant,” he said.
The security briefing issued to prisons says staff who suspect that mail contains illicit items should wear personal protective equipment for health and safety reasons and evidence preservation.