Drones are being increasingly used to smuggle drugs, mobile phones and other banned items into prisons, it can be revealed.
Figures obtained through a Press Association Freedom of Information (FoI) request show that in 2013 none of the unmanned crafts were discovered in or around English prisons.
But in 2014 this rose to two incidents, rocketing to 33 in 2015 - an increase of 1,550% in that period.
Items discovered include just the drones themselves, drugs, mobile phones and chargers, and USB drives.
The use of drones to smuggle traditional drugs, NPS (legal highs) and mobiles phones into prisons is of serious concern to the POA.
Leeds Prison and Lindholme Prison in Doncaster both recorded one drone incident between 2014 and 2015.
Incidents involving drones are rare, but we remain constantly vigilant to all new threats to prison security.
A report published in December by the HM Inspectorate of Prisons noted that illegal drugs, NPS and illicit medications may get into prisons in a number of ways - meaning it is not always possible to quantify exactly how many drugs are making it into prisons.
With supply routes differing from prison to prison, drugs have been discovered being thrown over fences in tennis balls, in large packages fired by catapults and being dropped by drones.
The report states that "easy access to illicit mobile telephones makes it possible to plan the drops carefully".
Figures revealed by the FoI show that across the incidents at English prisons, drugs were discovered on at least six occasions, mobile phones more than nine times and a drone itself recovered in 19 instances.
One of the biggest finds listed a drone, drugs, mobile phone, a charger and USB cards being discovered in December last year at HMP Oakwood.