The right to free movement for workers within the European Union was enshrined in Article 48 of the EEC Treaty in 1957. Nowadays, private labour market intermediaries – such as temporary work agencies and employment placement agencies – contribute to facilitating this labour mobility in their role as mediator between individual workers and organisations in need of labour. However, due to loopholes in regulation, some workers and vulnerable groups run the risk of being exploited by fraudulent agencies. This report examines how public authorities are currently regulating labour market intermediaries across Member States, highlighting the effectiveness or otherwise of different registration or licensing schemes. It also examines activities by social partners aimed at preventing the trafficking of labour. The overall aim is to contribute to the development of a best practice guide for public authorities to encourage better monitoring and enforcement of regulations deterring trafficking for the purpose of labour exploitation. An executive summary is available - see Related content.