As part of the support team of the European Platform tackling undeclared work, CSD is developing a series of papers, analyses and toolkits, aimed at sharing good practices and experiences among the Member States. Since 2016, the European Platform tackling undeclared work provides an EU-level forum that allows different actors, including social partners and enforcement authorities, such as labour inspectorates, tax and social security authorities, to engage in closer cross-border cooperation and joint activities. The Platform’s 2-year work programme for 2019-2020 includes activities enabling Platform members to deal with undeclared work through a holistic approach. The new work programme is building on work to tackle bogus self-employment and fraudulent letterbox companies. Four sectors that are heavily affected by undeclared work have been identified for specific action: agriculture; aviation; tourism; and the hotel, restaurant and catering sector.