Thousands of foreign fighters have travelled to Iraq and Syria in the year since Islamic State of Iraq and the Levant's (Isil) lightning sweep through the two territories. According to the most recent publicly available estimates, released by King's College London’s International Centre for the Study of Radicalisation in January, Tunisia has contributed the largest contingent, with some estimates putting the figure as high as 3,000.
The foreign loyalists can expect to join fighting battalions, or even take up positions in the extremist group's extensive bureaucracy, which implements Islamic law and harvests taxes across its territory. Saudi Arabia - a country battling Isil terrorism against Shia residents in its eastern province - is thought to be the second most prolific source of foreign fighters, with up to 2,500 people believed to have joined the fray in Iraq and Syria. (Please see figures below for more details)
Nearly a fifth of fighters are residents or nationals of Western European countries,and an estimated 1,200 people have travelled from France alone. These figures will have risen in recent months as Isil has attracted more fighters to help it consolidate control over three provincial capitals - Raqqa, Mosul and Ramadi.
This flow of foreign fighters has alarmed governments around the world, raising fears that returnees from may plot attacks in their home nations. Scotland Yard said that at least half of the 700 British residents - a statistic from the British police - suspected of fighting alongside Isil are now back in the UK.
When pressed last month on how the security services will treat the case of three schoolgirls who have reportedly escaped from Isil, after initially seeking to join the jihadist group in Syria, Home Secretary Theresa May said that decisions are made on a “case-by-case basis”.