Drug use in prisons is now "widespread", an official report has warned.
It said the scale of the problem is "significant" and has become more challenging in recent years, exacerbated by the emergence of psychoactive substances.
The strategy paper, jointly prepared by the Ministry of Justice and HM Prison and Probation Service, said: "The misuse of drugs in prison is one of the biggest challenges facing our criminal justice system today.
"Drug misuse is prevalent and contributes to violence, crime and vulnerability within prisons, which threatens safety and the ability of our hard-working prison staff to deliver effective regimes."
The document cited figures showing that, between 2012/13 and 2017/18, the rate of positive random tests for "traditional" drugs in jails increased by 50%, from 7% to 10.6%.
Statistics published last year also showed that the number of incidents where drugs were found in prisons in England and Wales rose by 23% to 13,119 in 2017/18.
Psychoactive substances
The paper said: "Drug use in prisons is now widespread, particularly in male local and category C prisons.
"The emergence of psychoactive substances such as synthetic cannabinoids has exacerbated the problem, and these are often used in conjunction with other drugs, while we remain aware of problems with the diversion and misuse of prescription medication."
Prisons are being provided with x-ray scanners, extra detection dogs and mobile phone blocking technology as part of efforts to stop drugs getting in.
Staff have also been issued with detailed guidance on handling incoming mail following attempts to post drug-laced paper into jails.
The ministry said its strategy centres around three objectives, restricting supply, reducing demand and building recovery.
Prisons Minister Rory Stewart said: "The threat drugs pose to the safety of prisons has never been greater and it requires a wide-ranging response.
"The Prison Drugs Strategy sets a clear direction for all those involved in reducing the impact of drugs in our jails.
"The potential benefits of this are huge, not only in the form of improved safety for officers and prisoners, but also in reduced re-offending and greater public safety."
