The numbers behind the worldwide trade in drones

There are more unmanned aerial vehicles (UAV) - or drones - being transferred between countries than ever before, according to data from the Stockholm International Peace Research Institute (Sipri).

Between 2010 and 2014, there were 439 drones exchanged compared to 322 in the five years previous to that.

Armed drones have become increasingly controversial in recent years following their use by the US in strikes against Pakistan-based militants. Critics say that even when specific targets are sought, far too many people are killed as collateral.

Although armed drones and airstrikes are most associated with the UAV debate - drones with the capacity to make armed strikes still make up a small fraction of overall trade - just 11 (2.5%) of the 439.

Armed drones were exported for the first time in 2007 when the UK received a delivery of two MQ-9 Reaper drones from the US, which were initially used in the Afghanistan conflict.

Last year, China became the second country to openly export armed drones by sending five to Nigeria for its fight with Boko-Haram. However, Sipri say there is also evidence that China sent some of the same CH-3 model to Pakistan in 2013.

This has prompted US to open up its own trade in armed drones to friendly and allied countries - previously it was just exporting to the UK.

The size of the trade: UK imports the most

In 2013, the US sent the huge (15-tonne) 1 Global Hawk to Germany. It is the largest drone ever exported, as well as the most expensive ($130m) and the one with the biggest range of travel (14,000km). Orders have also been placed by Nato, Australia, Japan and South Korea.

Do not be mislead by this chunky unmanned vehicle though, the number of drones changing hands is not that sizeable. UAVs made up just 0.3% of total major arms trade between 2010 and 2014, according to Sipri.

There were 35 different countries importing UAVs in the 2010 to 2014 period, nine more than between 2005 and 2009.

On top of that list of importers was the UK, which took 55 drones from Israel on top of six further armed UAV from the US - which adds up to more than a third of global deliveries between 2010 and 2014.

So where do all these drones come from? Mostly Israel

The middle eastern country is the largest exporter of drones. Between 2010 and 2014, it delivered 165 units across the globe. The US came second with 132, followed by Italy’s 37.

Since 1985, Israel has accounted for the majority (60.7%) of drone exports worldwide. Despite China’s move into armed UAV exports, it only supplied 0.9% of total exports during this last couple of decades.