Accepting they are not toys, and accepting they are increasingly and readily available, an assessment of threats should start with an examination of how they are being used by hostile, or potentially hostile, forces.
There are a number of instances where drones have caused a great deal of concern for safety and security.
Perhaps the most famous so far has been the Pirate Party flying, or perhaps more accurately, crash landing, a drone in front of Angela Merkel at a campaign rally in Dresden in 2013.
The Deputy Head of the Pirate Party, Markus Barenhoff, said;
The party admitted the crash was not part of the plan but German security forces, and those around the world, took note.
In 2014, the French security services investigated a number of reports of drones flying over their nuclear power plants.
Google may well obscure their mapping and satellite imagery of sensitive sites but if a £800 unmanned system can shoot geo-referenced 1080p HD digital video and 20mp still imagery of the same site in 15 minutes, those protections are simply irrelevant.
In 2015, a small drone crash landed onto the White House lawn. The owner, Howard Solomon III, lost control after wind blew it away from the Washington Monument he was taking photographs of.
Although there was no malicious intent, it demonstrated perfectly just how difficult they are to detect and counter. This incident was actually the second that year at the White House, four months earlier, an intelligence agency employee crashed a borrowed device after flying it out of his apartment window and losing control.
News organisations have started to use them, from Thailand to the Kent-based newspaper group, News Shopper. A freelance journalist was arrested for flying a drone near the scene of a Surrey caravan fire and in Davos, three BBC journalists were arrested for also flying a drone, near the World Economic Forum event in 2015.
More recently, the focus has been on the danger to aircraft, this from the Metropolitan Police in 2016;
As can be imagined, this incident created a significant response and highlighted serious concerns with passengers and aircraft operators alike
Some claimed that it was probably a plastic bag whilst others are still maintaining it was a UAS.
None of the incidents described above were linked with criminal or terrorist organisations but it is clear that these groups have recognised the value of commercial unmanned systems.
Mexican criminal cartels have used unmanned systems for the delivery of drugs and other contraband across borders and into prisons. The preferred tactic has been to use pre-programmed GPS coordinates rather than remote control and although payloads might be limited to a couple of kilogrammes at a time, they provide a high degree of delivery confidence.
It has also been reported that they have been used to monitor security forces locations during smuggling operations.
A US citizen, Rezwan Ferdaus, was sentenced to 17 years in prison in 2012 for a plot involving Al Qaida, C4 explosives and a remote-controlled model aircraft.
In the UK, there have been a number of incidents reported of criminals using quadcopters to deliver contraband to prisoners, Class A/B drugs and mobile telephones for example.
The image below shows a Phantom 4, available for less than £1,000, which was seized during Operation Airborne, a joint Caledonian Neighbourhoods Policing Team and the Metropolitan Police Special Constabulary operation to intercept these devices.
For unconventional and poorly resourced military or insurgent forces, commercial systems provide a low-cost entry into the unmanned world and have seen widespread use in recent conflicts in Libya, Ukraine and Iraq/Syria.
No month long training programmes or extended procurement processes.
In the conflict in east Ukraine, both sides have made extensive use of commercial unmanned systems. (Although the non-state actor definition would normally exclude government forces, I have included it here because of their use of commercial systems and hybrid force organisation)
Given the nature of the conflict and available evidence, it would suggest that this is a most ‘drone heavy’ combat environment, especially since both sides have them. There are many lessons that can be learned.
One really interesting aspect of the conflict (and probably worthy of several studies alone) is the crowdfunding initiatives both in Ukraine and abroad. This is an ongoing endeavour that seeks to fund items as diverse as covers for Grad rocket launchers to quadcopters. Chicago Automaiden is a US organisation that funds and develops unmanned systems and other items for use by Ukraine forces.
The Aerorozvidka (air reconnaissance) project has created a grass roots unmanned system provisioning and operations capability and they have made extensive use of octocopter designs and a modified version of the widely available DJI Phantom. The project has their own Facebook page and website.
Aerorozvidka was started in 2014 by Natan Chazin and a handful of others and has since played an important role in delivering design development, training and operational services to the Ukraine armed forces.
There are a number of other initiatives, certainly a sign of a nation pulling together and exploiting its technical resources. Working with universities and small technology companies with readily available and open source technology, the Ukrainian forces have managed to drive down costs and improve technical capabilities, especially in jamming resistance.
For many of these citizen groups involved with UAS operations it has been a tough journey, with many deaths and injuries, but capabilities are improving. When equipped with infrared cameras they have been used to provide overwatch security for checkpoints, support artillery observation and other reconnaissance tasks.
The separatist organisation has also used commercial UAS technology, even to the extent of arming those with hand grenades and rudimentary release mechanisms, but given they have access to Russian systems, probably not to the same extent as government forces.
This document provides an excellent overview of the efforts to counter Camcopters of the Minsk II Monitoring Mission.
Whilst the conflict in Ukraine has seen commercial UAs used mostly for reconnaissance and observation, ISIS and Syrian rebel groups have extended from this into weapons release modifications to them.
Using multiple camera angles and video post-production techniques, a number have turned this raw footage into an effective communication and propaganda tool. Imagine if these were showing attacks against British soldiers fighting in some future campaign.
Bloomberg published an article in Jul 2016 that highlighted many of the concerns;
At the beginning of September 2016, a video surfaced that showed a quad copter dropping a small free-fall explosive device onto government forces.
Since then, there have been a number of sightings of weaponised commercial drone systems.
The Center for the Study of the Drone at Bard College maintain a database of sightings, click here to view.
In October 2016, Le Monde and Middle East Eye reported on a use of ‘airborne IED’s.
It was subsequently reported that the drone was booby trapped, a victim initiated IED, and obvious source of interest.