The home states of multinational enterprises have in recent years sought to use public regulation to fill the gaps left by the absence of a binding labour standards framework in international law. This article examines recent home state initiatives to address forced labour, human trafficking, and slavery in global supply chains, and their interactions with private governance initiatives. Focusing on a case study of the 2015 UK Modern Slavery Act and 2010 UK Bribery Act, we analyse two distinct legislative approaches that policy makers have used to promote corporate accountability within global supply chains and explore the varied impacts that these approaches have on corporate behaviour. Empirically, we analyse codes of conduct, annual CSR reports, and supplier terms and conditions for 25 FTSE 100 companies to shed light into the impact of the legislation on corporate behaviour. We find that legislation that creates criminal corporate liability appears to spur deeper changes to corporate strategy, and argue that in the case of the Modern Slavery Act, the triumph of voluntary reporting over more stringent public labour standards seems to have undermined the effectiveness of recent governance initiatives to address forced labour in global supply chains.