Nuclear disarmament


At present, because of the continued existence of large nuclear arsenals around the world, the possibility of further proliferation of nuclear weapons and the risk of increased international instability and tension, we believe that the UK’s nuclear deterrent remains an important element of our national security. However, we will continue to take steps towards a safer and more stable world where countries with nuclear weapons feel able to relinquish them.

We believe that sustainable nuclear disarmament can only be achieved through a multilateral process. The Nuclear Non-Proliferation Treaty (NPT) provides the basis for global efforts to prevent the spread of nuclear weapons, to promote the safe and secure use of civil nuclear energy and to pursue the goal of a world without nuclear weapons.


Reducing the UK’s nuclear weapons stockpile

We are reducing the UK’s stockpile of nuclear weapons to no more than 180 warheads, and a maximum of 40 per boat. This will be complete by the mid-2020s.

Nuclear Non-Proliferation Treaty action plan

The Nuclear Non-Proliferation Treaty is reviewed every 5 years. A 64-point action plan was agreed at the 2010 Review Conference by nuclear and non-nuclear-weapons states. This demonstrates the broad international commitment to the NPT regime.

The plan included actions on nuclear disarmament, non-proliferation and the peaceful uses of nuclear energy. The government is working closely with all states to progress these actions across all 3 ‘pillars’ of the NPT (see Legislation section).

The action plan contains a number of specific recommendations on disarmament for the 5 nuclear-weapon states including the UK. We are discussing ways we can work together to make progress on these.

The next Review Conference will take place in New York in 2015.


The 2010 Strategic Defence & Security Review (SDSR) reaffirmed our commitment to maintaining a minimum effective nuclear deterrent, but also contained a number of new disarmament measures.

In May 2010 the government announced that it would reduce the overall size of the UK’s nuclear weapons stockpile to 225. Publishing information about the total number of weapons goes beyond our previous policy, which declared only ‘operationally available’ weapons.

Following a further review, in October 2010 the Prime Minister announced that by the mid-2020s the overall size of the UK nuclear weapons stockpile will reduce to no more than 180 warheads. No more than 120 will be operationally available.

In June 2011, the government announced the early implementation of these reductions.

We also announced a new, stronger assurance that the UK will not use or threaten to use nuclear weapons against non-nuclear weapons states party to the NPT. These announcements mean that the UK has been more transparent than ever about our arsenal and declaratory policy, which we believe will help to build trust between nuclear and non-nuclear weapon states, and contribute to efforts to reduce the number of nuclear weapons worldwide.


The NPT entered into force in 1970 and is the basis of the global nuclear non-proliferation regime. It consists of 3 ‘pillars’.

Pillar 1 relates to non-proliferation. The recognised nuclear-weapon states (China, France, Russia, UK, US) undertake not to transfer knowledge or equipment to other states, and non-nuclear-weapon states commit to not trying to acquire it.

Pillar 2 relates to multilateral nuclear disarmament. It commits all states party to pursue negotiations in good faith towards the cessation of the nuclear arms race and to multilateral nuclear disarmament as part of general and complete disarmament.

Pillar 3 relates to the peaceful use of nuclear energy. The NPT recognises that all states party have an ‘inalienable right’ to use civil nuclear power.

The 2010 NPT Review Conference concluded in New York on 28 May 2010 with an action plan covering all 3 ‘pillars’.