Western counter narcotics policies in Afghanistan failed dismally after opium cultivation surged to unprecedented levels. At the centre of this failed battle against illegal narcotics was the Anglo-American partnership. Far from working harmoniously, the alliance was separated by competing and opposing views of how to address the opium problem. These disputes led to open diplomatic clashes and friction within the wider Anglo-American relationship. This work provides the first definitive account of the United States’ and United Kingdom’s counter narcotics policies in Afghanistan and details the inside story of the policy-making process which underpinned their formulation and implementation. Through interviews with key policy practitioners on both sides of the Atlantic, this study reveals the complex picture of counter narcotics policies; highlighting key points of cooperation and contention and detailing the often contradictory and competitive objectives of the overall war effort in Afghanistan. An integral part of that explanatory analysis is also a more comprehensive account of the development of British counter narcotics policies than hitherto available. Building on the limited volume of work by previous scholars, this study presents previously unknown details regarding the decision-making process that underpinned key policies, including: compensated eradication (2002); UK appointment as ‘G8 lead nation’ (2002); and the transition of the UK’s role as ‘partner nation’ to the UNODC (2011). Furthermore, the study provides unique coverage of Anglo-American discord over aerial eradication (2004-2008). This issue was been covered by many academic and media reports over the course of the conflict but no research has provided in-depth analysis of events from policy makers’ perspectives in both governments within the context of their wider special relationship.