Complicity in Internationally Wrongful Acts Through State-Sanctioned Arms Transfers and Assistance

This thesis examines third-State responsibility for complicity through State-sanctioned arms transfers, focusing on the illustrative example of the United Kingdom’s arms exports to Israel during the 2023-present Gaza conflict and occupation. It argues that classical neutrality has been superseded by an integrated framework combining Common Article 1, Articles 6-7 of the Arms Trade Treaty, and Article 16 ARSIWA. The mental element for complicity has evolved from specific intent to foreseeability and conscious risk-taking (dolus eventualis). Critically, constructive knowledge crystallises into actual knowledge in saturated information environments – where the factual record of an ongoing conflict is sufficiently extensive and publicly available, that ignorance becomes legally untenable. Applying this framework, the thesis finds evidence that the UK operated within such an environment by late 2023-2024, yet knowingly maintained key arms export licences to Israel, demonstrating at minimum a failure of due diligence and, plausibly, reckless assistance bordering on complicity with the Internationally Wrongful Acts of Israel. Despite this doctrinal clarity, enforcement remains obstructed by structural and political constraints, shifting the onus of accountability onto domestic courts, with limited judicial intervention, that is largely deferential to executive discretion. The thesis concludes that future enforcement requires strengthened accountability measures through clearer articulation of risk-based knowledge standards and due diligence thresholds, stronger and more operational preventative duties linked to CA1, and overall enhanced transparency for decision-making for arms exports. Such a multilateral approach is essential to address the complexity of modern warfare and assert transfers as inherent legal risks – not mere policy discretion.