The Maintenance and Possible Replacement of the Trident Nuclear Missile System

Introduction and Summary of Advice

1.   We are asked to advise Peacerights on the legality under international law of the United Kingdom's actions with respect to the Trident nuclear missile system. The question on which our advice is sought is whether the UK is in breach of international law through maintenance of the Trident system or the replacement of that system by one with a similar yield. More specifically advice is sought on (i) whether Trident or a likely replacement to Trident breaches customary international law and (ii) whether the replacement of Trident would breach the Non-Proliferation Treaty 1967 (NPT), article VI.

2.   In our opinion, for the reasons which are set out below:
(1)   The use of the Trident system would breach customary international law, in particular because it would infringe the "intransgressible" requirement that a distinction must be drawn between combatants and non-combatants.

(2)   The replacement of Trident is likely to constitute a breach of article VI of the NPT.

(3)   Such a breach would be a material breach of that treaty.

For the full document please download the Opinion (.doc format) here