Whilst everybody is up in arms about the recent privacy scandals surrounding NSA’s ‘PRISM’ and ‘Boundless Informant’ programmes, another privacy storm is quietly brewing: the use of drones for surveillance purposes.

Currently, drones, or Unmanned Aerial Vehicles (UAVs) are mainly used for military purposes. They are excellent for reconnaissance and attack missions because there is no risk that a pilot will be shot down over enemy territory. Furthermore, drones are far more cost efficient than traditional manned aircraft.

The potential of drones has not gone unnoticed in the intelligence and law enforcement communities. Drones equipped with cameras can be used for domestic surveillance and law enforcement purposes. In the Netherlands drones have been used about a hundred times for law enforcement purposes in 2012.

Drones can be a valuable tool for law enforcement, but we should not disregard the privacy risks associated with their use. Drones have several distinct features that need to be taken into account when discussing their use for surveillance purposes.

First of all, drones are difficult to see with the naked eye, making it unclear when and where surveillance is taking place. The Dutch police for instance uses the Raven, which is a craft of about 1,5 metres flying at an altitude of 300 meters. The American MQ-9 Reaper drone, while significantly bigger, operates at an altitude of 5 kilometres also rendering it difficult to see. But even if drones can be spotted, it will be difficult to determine who is using them and for what purposes. Unlike a police helicopter it is difficult to put visible police decals on a Raven for instance. So a drone may be used by the police, intelligence agencies, or even private entities, resulting in much uncertainty for those observed.

Secondly, drones can observe far more than is currently possible with CCTV cameras. Drones can patrol an area of several square kilometres using both normal and infrared cameras. The Americans are currently working on a programme called ‘Gorgon Stare’ (what’s in a name) that allows them to observe an entire city using a special camera array mounted under an MQ9-Reaper. As a result, the scale of surveillance is increased. Furthermore, it is also possible to observe areas that are normally considered private (such as gardens or even the interior of a home).

Thirdly, drones can observe and follow individuals, something that is very difficult, if not impossible, using fixed CCTV cameras. The use of drones can quickly transform from general surveillance to targeted observation.

Finally, keeping PRISM and other surveillance programmes in mind, it is important to note that the images and video captured by drones can be stored and analysed for future purposes. This may lead to mission and function creep and will enhance privacy risks.

In my opinion these privacy aspects warrant special attention in the discussion on the use of drones for domestic surveillance purposes. If we do not have a fundamental discussion about these and other privacy risks of drones, we risk another PRISM scandal further down the line.