Abstract/Summary

The negotiation and subsequent entry into force of the Treaty on the Prohibition of Nuclear Weapons (TPNW) marked a momentous, though controversial, legal development in the pursuit of a nuclear weapon-free world. The TPNW establishes legally binding prohibitions on the use, possession, and development of nuclear weapons applicable globally on a non-discriminatory basis, alongside disarmament ‘pathways’ through which nuclear disarmament can proceed. However, each of the nuclear weapon possessing states (NWPS) has vigorously opposed the TPNW, raising questions as to what contribution the treaty can have in facilitating progress towards nuclear disarmament in the absence of the NWPS within a positivist, consent-based international legal system. Facing these concerns, this thesis aims to determine precisely what impact and influence the TPNW can bring as a legal instrument to the pursuit of a nuclear weapons-free-world. This is pursued in two ways. First, the discussion examines the ‘theoretical’ potential and contribution of the TPNW on the wider pre-existing international nuclear non-proliferation and disarmament legal regime by assessing the content of the treaty’s nuclear disarmament-related provisions, particularly the prohibitions and disarmament ‘pathways’ under Articles 1 and 4 respectively. Second, the thesis explores the ‘practical’ influence of the TPNW in reinvigorating nuclear disarmament-related discourse and progress within multilateral disarmament forums since 2017. This also examines the possible emergence of customary international law prohibitions on the use of nuclear weapons stemming from the adoption of the TPNW. Overall, this thesis offers an original, holistic account that explores the TPNW’s ability to advance the objective of nuclear disarmament. Ultimately, however, the conclusions reached suggest that while the TPNW has the potential to significantly contribute to nuclear disarmament law, its impact in practice remains limited so far. Time may therefore be needed for the TPNW to mature normatively and instituionally before its real value can be determined.