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Executive Summary - IND 2024

Monday 4 – Wednesday 6 March 2024 I WP3260


Wilton Park, in partnership with the Norwegian Ministry of Foreign Affairs and the UK Foreign, Commonwealth & Development Office (FCDO), hosted a dialogue on “Irreversibility in Nuclear Disarmament”. The dialogue centred around how to frame irreversibility in nuclear disarmament (IND) for inclusion in 2026 Review Conference of the Nuclear Non-Proliferation Treaty (NPT RevCon) discussions and documents. There was an appetite among the participants for more dialogue, wider engagement and the translation of high-level discussions into actionable steps that States and civil society can take now to further the IND agenda.

By shifting the IND dialogue to become more forward-looking to the 2026 NPT RevCon and beyond, the specific areas which garnered the most discussion included:

  • Defining IND and its relation to other concepts, such as verification, transparency and latency.
  • Separating how IND is considered in both the process to achieve disarmament and the resulting end state.
  • Developing a substantial list of areas from which to extract lessons for the IND community.
  • Introducing future steps for the IND community, including areas of further research.

This report is organised by those discussion areas and lists the specific ways in which participants, and the greater IND community, can ensure progress is made in the coming years towards irreversible nuclear disarmament


Wilton Park held its third dialogue in a series on “Irreversibility in Nuclear Disarmament”, which sought to build on previous academic and diplomatic work made since the March 2022[1] and March 2023[2] dialogues and August 2023 NPT Preparatory Committee (PrepCom) joint statement.[3]

This dialogue shifted the conversation to the future: how to move IND forward to the 2026 NPT RevCon and beyond. Wilton Park sought to further develop detailed thinking on the parameters and criteria of irreversibility and foster international dialogue between NPT States Parties and non-governmental organizations (NGOs) to critically engage with IND. The short-term goal was set to support work leading to the submission of a working paper to the 2026 NPT RevCon through building a shared understanding of IND, continued academic exploration of IND, workplan development and mutual support between States and NGOs. This work’s long-term goals are driving towards strengthening Article 6 of the NPT and preparing all necessary elements for when disarmament becomes a reality.

Defining IND and its relation to other concepts

A clear, common definition of IND is lacking, although participants disagreed if there is even a need for a definition. There is support for moving towards a common understanding, but having one, narrow definition could be limiting. Discussions on defining IND can be constraining and prove to be distracting from progress on IND-related issues; however, in spite of these reservations, there was progress on building a common understanding of IND and how it links to other concepts.

Irreversibility is a spectrum. It can be enhanced, but nothing is ever truly irreversible. For example, nuclear capacity cannot go to zero, but weapons can be irreversibly eliminated in a verifiable manner. Thus, judgements of irreversibility are subjective and are closely linked to trust and confidence.

Despite the progress made at this dialogue, there is still work to be done on building a common understanding in a number of areas, including in IND’s relationship to delivery vehicles and the concept of “complete” disarmament. Further conversations were had regarding IND’s relationship to the concepts of verification, transparency and latency.


Verification of IND does need a narrow definition as it differs from current, traditional discussions around verification. While IND and verification do overlap, they differ in scope and outcomes, and, therefore, should not be conflated as IND covers a broader set of items often not covered by treaties.

The community needs to be explicit about what is being verified: does this mean changes of physical material, facilities or something else? Further, there is a difference between verifying that something is irreversible and verifying that an action that has happened is not being undone.


Transparency was linked a number of times to IND, especially as it can help lead to greater trust, confidence and cooperation. It can help foster a virtuous action cycle where States continue to take cooperative measures towards IND via transparent actions.

Linkages between irreversibility, verification and transparency are important to explore and develop a common understanding of as they are the three key principles established in the 2010 NPT RevCon.[4]


Latency is in some ways the reverse image of irreversibility, and is thus also a spectrum. Determining what contributes to a State’s latency (or latent capability in the case of formerly-armed States) can help inform the IND regime of which specific areas should be considered for verification and monitoring in a disarming or disarmed world.

Some States think of latency as a deterrent in and of itself, which allows for some security during the process of disarmament; however, this goes against the disarmament norm, which calls for the reduced importance of nuclear weapons.

Discussions on hedging can be conflated with discussions on latency, but they should be separated as hedging requires active decisions. Further, some participants were hesitant to include latency as part of irreversibility conversations as the topic can distract and prove contentious, thus hampering collaborative progress on IND.

[1] Zuzanna Gwadera, “Irreversibility in Nuclear Disarmament,” Wilton Park, August 2022, in

[2] J. Luis Rodriguez, “Moving forward on Irreversibility in Nuclear Disarmament”, Wilton Park, September 2023, in

[3] “First Preparatory Committee for the 2026 Non-Proliferation Treaty Review Conference: irreversibility statement”, UK Foreign, Commonwealth & Development Office and Delegation of Norway, 11 August 2023, in


Irreversibility in nuclear disarmament 2024 – report


Defining IND and its relation to other concepts

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