This article documents the significant successes and major setbacks of a campaign led by Latin American cleaners for union recognition and better pay and conditions at the University of London. It shows how they overcame fear, resignation, intimidation, racism, poverty and cultural and linguistic alienation to find their political agency. However, their collective empowerment was met by dismissals and deportations. The article argues that there are a number of important lessons for the trade union movement to learn; namely, the need to have specific legal and campaigning strategies in place to defend its migrant activists as well as calling for the regularisation of ‘irregular’ workers. In sum, the struggle for immigrant rights is at the cutting edge of the global working-class fightback.