Unmanned aerial systems have been spotted flying over or nearby UK military facilities, according to logs released by the government (Picture: Getty)

A series of drone incidents triggered investigations after sightings over or near UK military bases last year, newly released files show.

The cases recorded by the Ministry of Defence (MoD) included a pilot reporting an unmanned aerial vehicle (UAV) at 20,000ft. 

Another incident concerns a drone, believed to have been a quadcopter, which was said to have ‘hovered over barracks’.

The UAVs were also recorded as coming within close proximity of military facilities, according to the information released by the MoD’s Directorate of Security & Resilience.  

One was sighted over the roof of a building while another landed on an ‘upper roofed area’. 

In total, there were 21 incidents between January 2022 and February this year, the response to a request by Metro.co.uk under the Freedom of Information Act shows.

On one occasion a security team was recorded as having located the operator. The incident report reads: ‘Report of drone flying. 

‘Officers conducted area search, operator located. Spoken to by officers, who viewed footage from drone, operator voluntarily deleted all footage.’

The widespread availability of drones has had ramifications for the UK’s critical infrastructure (Picture: Richard Newstead/Getty)

Only one of the other reports, where a drone was being used at a pre-planned event, shows any sign of the operators having been located.

Two other incidents concerned an object described as a ‘drone/microlight glider’ which was seen by ‘multiple witnesses’ in one case.  

Another report in the list of incidents states: ‘A drone (believed to be a quadcopter) hovered over barracks.’ 

Area searches were carried out in seven cases but no evidence of UAV activity was found. 

The log in another of the incidents states: ‘Report from pilot of drone at 20,000 feet. Nothing seen from the ground, area search carried out for operator, no trace.’ 

A military facility’s own systems detected a UAV in one case. The log reads: ‘Drone system activated, showing drone. Officers attended, no trace.’

The UK is seeking innovative solutions in order to deal with the threat from unmanned aerial systems (Picture: Getty Images/Westend61)

The information has been released at a time of heightened international concern about aerial spying by foreign powers.

A Chinese balloon was shot down by the US off the coast of South Carolina last month, with the Pentagon saying the craft had been used to spy on ‘strategic sites’. Europe is among at least five continents targeted by Beijing with the high-altitude balloons over the past few years, according to White House and Pentagon sources. 

The ability to weaponise drones, as evidenced on the battlefield in Ukraine, and to co-ordinate and interlink the UAVs in ‘swarms’, has emerged as another aerial threat to critical infrastructure.  

A swarm was reported on an unspecified date at a nuclear licensed in the UK between January 2014 and July 2020, according to the Office for National Regulation. No other details were released.

A group of up to six drones was reported to armed police ‘over and around’ Capenhurst nuclear site in Cheshire in July 2019, according to another disclosure from the Civil Nuclear Constabulary.

Such incidents are cloaked in secrecy by the various agencies involved on national security grounds and it is not known if the two reports are linked.

The evolving use of drones and their ability to be deployed as attack vehicles has led to security concerns (Picture: Richard Newstead/Getty)

Drones, along with any type of unmanned aircraft, are banned under the Air Navigation Order from flying in the airspace of nuclear installations. The Civil Aviation Authority says that ‘flying may be restricted’ around other sites including military ranges, royal palaces and government buildings.

The new reports come at a time of heightened tensions between the West and China and Russia, which have each been linked to concerted physical and cyber spying operations in the UK. 

Peter Burt, of Drone Wars UK, said: ‘These incidents highlight the potential that drones have to disrupt security arrangements. 

‘Although most of the cases were probably the result of careless use by irresponsible owners, there is certainly a risk that some of them were more malicious in their intent.  

‘It’s notable that in many of the cases the authorities were unable to trace the drone or its operator, which highlights the difficulties in countering the use of drones for illegal purposes. Drones are easily available and can be bought by anyone to use for criminal purposes.’

Mr Burt, who has studied UAV use and is part of the Nukewatch monitoring network, highlighted the weaponisation of drones, including as ‘kamikaze’ systems used to deadly effect in the Middle East and Ukraine.  

‘Drones bought off-the-shelf have been adapted to deliver weapons by a number of non-state groups during conflicts in the Middle East, and in the Ukraine war,’ he said. ‘We have seen how even the simplest drones can be used for reconnaissance and intelligence-gathering. 

‘The government is planning to deregulate UK airspace to allow greater commercial use of drones, meaning that drones will become far more intrusive into our everyday lives. These incidents give an indication of the difficulties that we can expect to arise in future in tracking down and tackling problems caused by rogue operators.’

An identifying number on a drone which was examined by researchers after being downed by Ukrainian forces (Picture: Conflict Armament Research)

The UK government is undertaking work to enhance the national response to the threats posed by increasingly sophisticated and widely used aerial systems at home and abroad. 

This includes through the Defence and Security Accelerator, a project to find innovative ways to mitigate hostile use of the systems and the RAF’s Project Synergia, which has delivered counter-drone technology. 

A Ministry of Defence spokesperson said: ‘We have robust security measures in place at all defence sites to respond to such incidents. 

‘While we cannot comment on specific security arrangements or procedures, we continue to invest in a range of measures to tackle future threats, including counter-drone technology.’ 

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Drones were sighted over or near UK military facilities more than 20 times last year, according to a new disclosure.