This report explores the links between trade unions and workplace training, and the potential benefits of social partnership in the skills system. The UK is relatively unusual in having no formal role for trade unions in the training system. In most advanced economies, trade unions and employers work alongside government in shaping the skills system. There is significant evidence -- both in the UK and internationally -- linking trade unions and collective bargaining to higher employer investment in skills. There is also evidence to suggest that unions are particularly effective at engaging low skilled workers in training. The report sets out how building a social partnership approach could help deliver the government's aim of levelling up skills and prosperity across the UK after the coronavirus crisis.