One drone is seized every week at a jail holding inmates in the worst conditions inspectors have seen, according to a scathing watchdog report.
HM Inspectorate of Prisons highlighted the widespread use of the flying devices in a document that slammed the "squalid" state of HMP Liverpool.
The drones, which are used to carry drugs and other illicit items, are part of a "substantial problem" at the prison, with staff recovering 32 of the gadgets in six months prior to September's inspection.
Drone have become a major issue in British prisons, the technology used to smuggle items including mobile phones and drugs with an estimated value of up to £1.2 million.
Concern over the conditions at HMP Liverpool, a category B facility holding 1,115 men at the time of the inspection, first surfaced at the end of last year when details of the report were revealed by the BBC.
In a catalogue of critical findings, the assessment said:
- Drugs were readily available: nearly two-thirds of inmates in a survey said they were easy to get hold of
- Four prisoners had taken their own lives since the previous inspection and two more suspected suicides occurred shortly after the latest visit
- Many cells had broken windows with dangerous jagged glass, damp, leaks and broken or blocked toilets
- Communal areas were in a "decrepit" state and there was a significant problem with cockroaches and rats throughout the jail
- Violence of all kinds had increased, with assaults on staff more than tripling compared with the last assessment in 2015.
"The inspection team was highly experienced and could not recall having seen worse living conditions than those at HMP Liverpool," Chief Inspector of Prisons Peter Clarke said
"Many cells were not fit to be used and should have been decommissioned. I saw piles of rubbish that had clearly been there for a long time, and in which inspectors reported seeing rats on a regular basis."
Clarke raised particular concerns over the case of one vulnerable man with complex mental health needs who was held in a cell that had no furniture other than a bed.
"It should not have needed my personal intervention for this man to be moved from such appalling conditions," he said.
The chief inspector concluded there had been an "abject failure" to offer a safe and decent environment at the prison.
He added: "This report makes it crystal clear that leaders at all levels, both within the prison and beyond, had presided over the failure to address the concerns raised at the last inspection."
The Commons Justice Committee will hold an evidence session on the findings next week.
Its chairman Bob Neill said: "This inspectorate's report is one of the worst I have ever seen."
Michael Spurr, chief executive of HM Prison and Probation Service, acknowledged the conditions at the prison were "unacceptable".
He said: "We are committed to fixing this, have already made changes where we can, and have today published a comprehensive action plan to address the Chief Inspector's concerns.
"Following the inspection we took immediate action to rectify the situation."
A new governor has been appointed, cleanliness has been improved and a maintenance backlog almost halved, he said.
Spurr added: "Liverpool has a dedicated staff who are committed to providing a safe and decent environment for prisoners."
The Ministry of Justice has announced a number of measures to stem the flow of contraband into prisons, including a specialist unit to counter the threat from drones.