Drone smuggling has led to a "step change" in the illicit drugs trade behind bars in Scotland, according to the jails watchdog.
HM Chief Inspector of Prisons, Wendy Sinclair-Gieben, said that prisoners and staff at HMP Perth had raised concerns over drug use, with some inmates having extreme reactions to synthetic drugs and new forms of benzodiazepines.
In a separate incident, a drone that crashed in the grounds of HMP Edinburgh was found to contain ceramic knives, drugs, mobile phones, and items with a prison value of £75,000.
The Scottish Prison Service said it welcomed the report and praised the "strong management" and "committed" staff working at HMP Perth.
The disclosure comes after it emerged that criminals in Scottish prisons are becoming "aggressive and violent" amid a new wave of psychoactive drugs being smuggled into cells.
Scottish Conservative justice spokesman Russell Findlay called on SNP ministers to "admit the scale of the problem and give frontline prison staff the support they need".