Colin C Williams is Professor of Public Policy in the Management School at the University of Sheffield in the United Kingdom. For the past 30 years, he has been researching the issue of undeclared work and how it can be tackled. Since 2016, he has been chief expert supporting the European Commission’s European Platform Tackling Undeclared Work. From 2018, he has been chief advisor on undeclared work to the West Balkans Regional Cooperation Council. He also works extensively with the International Labour Organisation (ILO) on formalising the informal economy in emerging economies.