At a time of great international tensions, where certain states openly challenge multilateralism and a rules-based international system, the UK government has a choice: to engage constructively with signatories and parties to the TPNW and foster a culture of dialogue and compliance, or to see its influence over disarmament policymaking diminish. Worse, the government could risk undermining initiatives under the TPNW that serve our common goals. As a strong supporter of international law (the government’s 2015 National Security Strategy and Strategic Defence and Security Review identifies “strengthening the rules-based international order and its institutions” as a priority), the UK has an interest in ensuring the treaty makes an effective contribution.

A positive response by the government to the TPNW could include:

• Fostering a dialogue with countries and organisations working on the TPNW, on how the treaty can make an effective contribution to disarmament
• Investigating how the UK could engage constructively with the treaty and other states’ work under it. This could be done within a broader examination of the UK’s international nuclear policy – in the context of rising nuclear tensions, and concerning developments such as the US’s new nuclear policy

Points on which the UK government could constructively engage with the TPNW directly include:

• Attending meetings of the TPNW as an observer: the government should have an accurate picture of the work that is proceeding – particularly to avoid wasting diplomatic effort on inaccurate notions, such as that this treaty poses a threat to the NPT, which was a common misconception during the TPNW negotiations
• Verification: during the negotiation of the TPNW, specific verification plans were left for future agreement when states with stockpiles joined the treaty. Given its work on this issue, the government should seek to contribute its expertise to any discussions, in order to ensure that the highest standards are maintained – even if it is not party to the treaty
• Addressing nuclear harm: the treaty provides an opportunity for a renewed focus from the international community to address the legacies of nuclear testing, and to support sustainable development in affected countries. Past treaties with similar provisions have helped to strengthen good practice and raise standards of assistance for individuals and communities affected. The UK should seek to provide expert input and funding to these discussions and processes, given our history of conducting nuclear tests in other countries

The Treaty on the Prohibition of Nuclear Weapons does not represent a challenge to alliances such as NATO or to the UK’s international standing – rather, it seeks to address the narrow issue of the unacceptability of nuclear weapons, as technologies that no country should ask their militaries to be willing to use when commanded. UK soldiers are not asked to use chemical or biological weapons because of the unacceptable harm they inflict – but the harm that would be caused by a nuclear weapon is of a completely different magnitude.

The global Red Cross and Red Crescent movement has called on all states to join the Treaty on the Prohibition of Nuclear Weapons,10 as have UN institutions. The UK will find itself increasingly out of step with the international community if it continues to reject engagement with the treaty – but could provide global leadership if it does respond positively.