Chief inspector Charlie Taylor has called for urgent action to be taken after an unannounced inspection of HMP Long Lartin, near Evesham, in October found serious concerns for safety and security.
The report stated: “Large quantities of drugs and other illicit items were entering the prison, especially on drones.
“Physical security and counter measures were not robust enough and neither national nor local leaders had addressed this longstanding problem with sufficient urgency.”
The category A prison was found to have thriving economies of drugs, phones and weapons, with security measures such as protective netting and CCTV falling into disrepair.
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Mr Taylor said: “It is highly alarming that the police and prison service have, in effect, ceded the airspace above two high-security prisons to organised crime gangs which are able to deliver contraband to jails holding extremely dangerous prisoners.
“The safety of staff, prisoners and ultimately that of the public is seriously compromised by the failure to tackle what has become a threat to national security.”
West Mercia Police says it is actively working to deal with the problems facing the prison.
Detective chief inspector James Bamber of West Mercia Police said: “We recognise the current difficulties being faced with the use of drones at HMP Long Lartin and, as a direct response to the issue, we have plans in place to respond robustly to drones over the prison airspace and intelligence about drone use.
“Earlier this month, a car was stopped and searched and a drone recovered in the area of South Littleton after officers responded to a drone spotted over the prison.
“Three people in the car were arrested and enquiries continue.”
Mr Taylor added: “The prison service, the police and other security services must urgently confront organised gang activity and reduce the supply of drugs and other illicit items which so clearly undermine every aspect of prison life.”
The report has led to criticism from Nigel Huddleston, MP for Droitwich and Evesham, who said: “This report reveals alarming security breaches at HMP Long Lartin.
“Having visited the prison several times, I have seen some of the deterrents in place, such as screens and nets, to prevent the delivery of contraband, however, it is clear that more needs to be done to address the scale of this issue.
“I will be writing to the minister of state for prisons to ask for a clear plan to tackle this problem.
Additionally, I have pre-arranged a visit to Long Lartin in my diary, during which I will discuss this issue directly with the governor and others.”
DCI Bamber added: “Communication between police and the prison is regular, with intelligence, information and prevention tactics shared amongst partners.
“We will continue to work with HMP Long Lartin and act swiftly to reports of drones within the airspace.”
The Worcester News approached Long Lartin for a comment but has not received a response.