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Foreign Fighters and the Returnee Threat

Foreign Fighters and the Returnee Threat

The Syrian conflict has been the most socially mediated war in history. In response, ICSR has developed some of the most sophisticated open-source methods used by academics today to better understand the origins, role and involvement of the foreign fighters participating in it.

This culminated in the creation of a database containing information on more than 700 Western volunteers, providing an empirical basis for quantifying the experiences of these fighters. This research was augmented by on-the-ground fieldwork and interviews with more than 100 foreign fighters, which were conducted during their time in theatre.

In addition to this, ICSR curates a number of subsidiary databases based on data collection from both open and closed sources. One of these comprises a codified archive of more than 4,000 entry records of Islamic State (ISIS/ISIL/Daesh) volunteers, consisting of an itemised breakdown of the paperwork they completed when first joining the movement. We also maintain open source databases relating to Islamic State attacks in the West, and returnee accounts.

These rich empirical sources provide the basis of our ongoing work to quantify, contextualise, and explain the role of foreign fighters in the Syrian conflict, their potential menace to the West, and the likelihood of a so-called ‘returnee threat.’


  • Advising governments, law enforcement, intelligence on how to curb the flow of foreign terrorist fighters;
  • Understanding the motivations and drivers of radicalisation for those becoming foreign terrorist fighters;
  • Contextualising and assessing the in- theatre threat profile of those who become foreign terrorist fighters;
  • Assessing the returnee threat;
  • Exploring opportunities for deradicalisation;
  • Providing insights on counter-messaging and campaigns.

Recent Policy Reports

  • Mar122019

    ICSR Event – Talk & Discussion with Peter Neumann at House of Commons, Tuesday March 19th, 6pm

    Where: Committee Room 12, Palace of Westminster, Westminster, London SW1A 0AA When: Tuesday March 19th, 6pm Rehman Chishti…

    Read more
  • Mar012019

    ICSR Event – Conceptualising the Role of Ideology and Ideas in Extremism, Thursday March 14th, 5.30pm

    Where: King’s College London When: Thursday March 14th, 5.30pm ICSR is delighted to invite you to an…

    Read more
  • Feb212019

    ICSR Event – Expert Talk On Counter-Terrorism in Indonesia, Wednesday March 6th, 5.30pm

    Where: King’s College London When: Wednesday March 6th, 5.30pm ICSR has the pleasure of inviting you to…

    Read more

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