Al-Sahwa’s origins date back to the 1950s and 1960s, when thousands of members of the Muslim Brotherhood fled violent repression across the region, especially Egypt, and came to the conservative kingdom.

North Africa countries have adopted an overwhelmingly legalistic approach to returning foreign fighters. In line with the 2014 UNSC Resolution 2178, which required countries to take steps to address the foreign fighter phenomenon, most countries (with the exception of Libya) now have legal frameworks for prosecuting returning foreign fighters, for the most part for having joined a terrorist group abroad. Therefore, returning foreign fighters who are detected at official ports of entry will face arrest.

Like the Baathist ideology in its time, IS’s takfirist discourse, excommunicating Muslims on the basis of their supposed apostasy and promoted by Jordanian jihadist Abu Musab al-Zarqawi and his Iraqi followers, is inseparable from the cycles of civil conflict that have plagued Iraq. It may re-erupt as IS has not been entirely defeated on the ground.

Central to the Saudi deradicalization approach is a process known as munassaha, which roughly translates as ‘counselling’. The process starts in prison and involves clerics engaging with convicts to persuade them that their notions of jihad are based on a misinterpretation of the Koran. However, the Saudi authorities say the success rate of their approach has been as high as 90 per cent

If jihadi groups continue to enjoy a similar level of online freedom over the next ten years, it will be relatively easy for committed entrepreneurs to build networks and plan operations. Jihadi groups outside Europe will also be able to recruit foreign fighters and direct attacks in Europe.

If the jihadi radicalization problem in Europe does indeed get worse, it may be worth considering radical new approaches, both of the soft and the hard kind. Perhaps Europe needs to spend significantly more to improve education in immigrant-heavy areas such as imposing longer prison sentences for terrorism offences