The current economic crisis, the consequent rise of unemployment and the limitation of welfare resources in many Western European countries is resulting in the worsening of working and living conditions of a significant part of the EU citizenship. The raise of low-skilled immigration towards such countries is increasingly perceived as a 'threat' for the host societies. Conflicts and differences between national and migrant workers are becoming increasingly manifest, not only in the labour arena but also in the wider society. Discriminatory sentiments and episodes of violence concerning ethnic minorities are spreading. In the applicant's view, the responses of the social actors to the interplay between migration and employment in the host countries will be important in shaping the future of Europe's social fabric. Among such actors, trade unions play an important role not only because immigration is primarily linked to labour but also because many conflicts occur in the labour arena both at the individual and collective level. This project aims at analysing trade union responses to immigration, immigration policies and a broad range of migrant workers, and at understanding the trade unions' (actual and potential) role in the economic and social integration of immigrants. Furthermore, it focuses on the trade union's role in mediating conflicting interests between national and migrant workers. The research develops a comparative international perspective by looking at a national context particularly affected by recent immigration (UK) and expanding on a previous comparative study on Italy and the Netherlands carried out by the applicant in her doctoral research. The aim of the comparison is a) to highlight differences in trade unions' formal debates, actions and outcomes related to the inclusion of migrant workers across the three countries and b) to point out explanatory variables and mechanisms for observed differences. The analysis addresses three main aspects: 1) factors that influence union stances towards labour immigration, immigration policies and migrant workers themselves - particular attention will be devoted to analyse the influence of the European policies related to immigration and free movement of labour on national trade unions responses; 2) the effects of union attitudes on immigration policies and migrant workers; and 3) the dynamics and methods of trade union interaction with migrant workers. Being situated at the intersection between migration studies and employment relations, this research will contribute to the scholarly debate in these fields: a) migration studies (the integration of migrants in host European countries in the context of the current economic decline and increase of social hostility); b) comparative employment relations (revitalization studies and varieties of capitalism approaches); c) the sociology of labour and labour market studies (analysis of labour market dynamics in terms of increasing flexibilization and migration); d) the Europeanization of migration policies debate. Furthermore, by focusing on social cohesion, the inclusion of migrants in the labour market and host societies, this research has the potential to address sensitive social issues and to highlight best practices and responses. Through the dissemination of research findings - inside and beyond the academic sphere - and the promotion of dialogue with potential beneficiaries and users, this research aims at resulting in concrete proposals for action.