This is the final of three Thematic Reports published as part of a CREST-funded project carried out by a team of researchers at City, University of London, and Cranfield University at the Defence Academy of the United Kingdom. With the objective of better understanding Tamil diaspora communities’ attitudes and engagement in the Sri Lankan civil conflict (1983-2009) and its aftermath, the project explores diaspora and refugee communities’ relationship with the changing socio-political environment in the homeland, exploring what shapes and influences processes of radicalisation or moderation among these communities. It recognises that the socio-political circumstances in which these processes develop are often crucial to understanding why a community or individuals within that community abroad act in a certain way; this includes analysis of different scales and levels of engagement, both in home and host countries, as well as different ‘areas’ of engagement, which can include social, economic and political interactions. The three thematic reports produced as part of this project cumulatively build a comprehensive picture of the state of knowledge on political action among diaspora, refugee and asylum populations. The theoretically-informed, literature-and evidence-grounded conclusions arising from these three thematic reports are therefore of relevance beyond the case of Sri Lanka. Thematic Report One discussed how four analytical concepts, diaspora, transnationalism, cosmopolitanism, and translocalism, have come to frame the academic discussion on overseas politics and the potential of these concepts to shed light on the relationship between mobility and political action. Thematic Report Two complements the previous report’s broad conceptual discussion by specifically focusing on an analysis of the context and drivers of political action among diaspora and refugee populations, and engaging with the term ‘refugee politics’. The current paper – the final Thematic Report – analyses the growing ‘securitisation’ of refugees and other forcibly displaced populations and calls for greater consideration of structural vulnerabilities in the forced migration and displacement cycle that increase the risk of radicalisation, extremism and related political behaviours.ESRC Award: ES/N009614/1