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Nuclear weapons: At a glance

This page has been replaced by a new Commons Library collection: Nuclear weapons, disarmament and arms control, and will no longer be updated.

Nuclear weapon states

There are nine countries in the world that possess nuclear weapons. According to the Stockholm International Peace Research Institute (SIPRI), between them they hold an estimated 12,241 nuclear warheads, 9,614 of which are thought to be operational (PDF).

The House of Commons Library has written a series of papers that briefly examine the nuclear policies, capabilities and modernisation programmes of the nine nuclear weapon states. 

Challenges of transparency 

Transparency is a major challenge, however. Even in the most open of democracies information on nuclear weapons programmes is largely classified. Information is not widely available and, for those countries motivated either by threat perception or conventional military inferiority, the tendency to exaggerate the extent, or operational nature, of their nuclear arsenals is commonplace.

As a result, there can be significant disparity in the estimates of each state’s active arsenal, reserve stockpiles of operational warheads and those warheads awaiting dismantlement. Information on spending related to nuclear weapons can also be limited. This lack of openness is a particular difficulty in relation to those states that operate outside the framework of the Nuclear Non-Proliferation Treaty (NPT) and the International Atomic Energy Agency.

Commons library briefings 

Overview: where are all the world's nuclear weapons?, July 2022

Nuclear weapons profile: United Kingdom, June 2025 

Nuclear weapons profile: Russia, December 2024 

Nuclear weapons profile: Israel, June 2025 

Nuclear weapons at a glance: China, July 2022

Nuclear weapons at a glance: United States, July 2022

Nuclear weapons at a glance: France, July 2022

Nuclear weapons at a glance: India and Pakistan, July 2022

Nuclear weapons at a glance: North Korea, May 2022

These papers replace Commons Library briefing, Nuclear Weapons – Country Comparisons 9 October 2017.

They should be taken as correct at the time of writing, and will be updated periodically.

Aspirant/ threshold nuclear states

Over the years various states have been identified as nuclear threshold states, either by default because of the sophistication of their civilian nuclear programmes, or because of their nuclear weapon aspirations.

Iran is one such state. The following House of Commons Library briefings provide further detail on Iran’s alleged nuclear programme and the status of the Joint Comprehensive Plan of Action (JCPOA):

The E3 triggers snapback sanctions against Iran 2025, September 2025 

Israel-Iran 2025: Developments in Iran's nuclear programme and military action, June 2025 

US-Iran nuclear talks 2025, May 2025 

What is the status of Iran's nuclear programme and the JCPOA?, October 2024 

Arms Control 

Nuclear disarmament and non-proliferation is under threat as the arms control regime governing nuclear weapons is increasingly undermined. 

The following Commons library briefings examine the historical pressures on that regime and efforts to establish new nuclear arms control measures:

Russia's use of nuclear threats during the Ukraine conflict, December 2024 

Treaty on the Prohibition of nuclear weapons, June 2022

Treaty banning nuclear weapons: What does this mean for the UK?, November 2020 

Prospects for US-Russian nuclear arms control, July 2020 

Demise of the Intermediate-Range Nuclear Forces (INF) Treaty, September 2019 

Nuclear weapons: Disarmament and non-proliferation regimes, June 2016