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 publicity available 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 IS 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. IS will be more violent than ever in order to survive. Nearly a fifth of fighters are residents or nationals of western European countries, and an estimated 1,200 people have travelled from France alone.