As David Cameron announces that he wants more defence spending on drones (among other things), we take a brief look at the facts and issues surrounding the unmanned aerial vehicles.

How common is the use of drones worldwide?

Drone in Afghanistan
A drone flies over Kandahar airfield, Afghanistan (Kirsty Wigglesworth/AP)

The use of unmanned aerial vehicles, or drones, by the military is now commonplace across the world, with the machines often being used for reconnaissance and precision strikes.

What kind of drones do the British military use?

Mini drone
Service personnel holding a Black Hornet, a Vertical Take Off and Landing (VTOL) and Unmanned Air Vehicle (UAV) (Rui Vieira/PA)

The RAF’s drones range in size and capability, with Britain’s systems ranging from huge Reapers – armed with Hellfire missiles and laser-guided bombs, to tiny hand-held mini helicopters named Black Hornets.

Is a drone completely autonomous?

Drone control room
Ground Control Station for the Remotely Piloted Air System (RPAS) Reaper for XIII and 39 Squadrons (Rui Vieira/PA)

Each drone is packed full of technology such as TV cameras, image intensifiers, radar and infra-red imaging.

But that doesn’t mean they “think” for themselves. Someone needs to programme the machinery for a start, and there’s always a crew on the ground either working the controls – or at least keeping an eye on what they’re doing.

How have drones been successful against Britain’s enemies?

Car blown up
A destroyed car that was carrying militants in the Sawmaa area of al-Bayda province, Yemen (Nasir al-Sanna’a/AP)

Governments say drone strikes have resulted in the deaths of hundreds of militants in countries such as Pakistan and Afghanistan, including high-ranking members of al Qaida.

Last month a US strike in Yemen is thought to have killed Nasir al-Wuhayshi, the leader of al Qaida in the country.

Why are drones controversial?

An anti-drone activist in America
An anti-drone activist in America (Steve Marcus/AP)

Campaigners claim many more civilians have died as a result of these strikes and they dispute how precise their use actually is.

Human rights group Reprieve claimed that more than 1,100 people have been killed by drone attacks in Pakistan and Yemen between 2002 and 2014.

Is the military managing drones’ negative image?

Drones system
Service personnel holding a Tarantula Hawk (T-HAWK), a Mini Unmanned Aircraft System (MUAS) (Rui Vieira/PA)

Due to the negative connotations surrounding the word drone, a high ranking commander in the Royal Air Force previously said military chiefs should step away from using the term because it elicits ideas of unaccountable computerised technology.

Air Vice-Marshal Phil Osborn, Joint Forces Command, said he wanted the public to know that at the heart of unmanned air technology used by British forces in warfare there are highly skilled professionals.