Drones have been described as a "threat to national security," according to the UK's prisons watchdog, following a significant rise in the delivery of weapons and drugs into high-security prisons, The Guardian reported on Tuesday.

Charlie Taylor, the chief inspector of prisons, urged the British government and the police to take immediate action after investigations revealed that terrorist suspects and criminal gangs may escape or assault guards due to "seriously compromised" safety.

Inspections have revealed that high-security prisons like HMP Manchester and HMP Long Lartin were plagued by booming underground economies, with narcotics, mobile phones, and firearms being sold. In addition, basic security measures, such as anti-drone netting and CCTV, had deteriorated.

A report released on Tuesday by Taylor revealed that authorities had essentially allowed organized crime gangs to control the airspace above these prisons, despite housing extremely dangerous inmates.

This failure to address the issue, Taylor warned, compromised the safety of staff, prisoners, and the public, posing a significant threat to national security.

Long Lartin inspectors discovered that "large payloads of illicit items" were being delivered, causing fights over drug debts and contributing to "low morale" among personnel. 

Taylor issued an urgent notice to HMP Manchester (formerly Strangeways) after discovering that inmates were burning holes in supposedly secure windows to receive frequent drone deliveries. The notification pointed out that some of these deliveries were large enough to disrupt prison order and potentially facilitate escapes, with inmates even threatening contractors who attempted to repair the windows.

Sophisticated drones, equipped with infrared technology and capable of carrying up to 7kg of contraband, are being used to deliver illicit items to prisons under cover of darkness. While some prisons have counter-drone measures to detect UAVs, few can actively prevent these devices from reaching their targets, The Guardian noted.

In November, Taylor expressed concern about drones, predicting that it was only a matter of time before weapons were smuggled in.

A recent report on HMP Garth revealed that the frequent drone activity was so widespread that an inmate compared it to an "airport".

The prisons watchdog has raised concerns about the strain on new probation officers handling an increase in early-release convicts, with many feeling overwhelmed and counterproductive.

The Guardian reported in July that prison governors in England and Wales had been cautioned that jails will be so overcrowded that they will struggle to accommodate any more inmates.

Martin Jones, the chief inspector of probation, reported that 1 in 10 probation officers left the service last year due to heavy workloads following reports of the government releasing around 2,000 offenders under the SDS40 plan to ease prison overcrowding.