TPNW’s first Meeting of States Parties in Vienna: fact sheet


A new United Nations agreement – the Treaty on the Prohibition of Nuclear Weapons (TPNW) – entered into force in 2021 making nuclear weapons illegal in the countries that sign it. This is the first meeting (1MSP) of the states that have ratified the treaty, to discuss what next for the TPNW.

When and where?

Participants will gather at the United Nations building in Vienna between 21st-23rd June 2022.


States that have deposited their instrument of ratification or accession 90 days prior to 1MSP will be able to participate as states parties, and thereby entitled to voting and other rights.

Other states can attend as observers. Civil society will also be in attendance.

Background to TPNW

The requirement for nuclear disarmament has been enshrined in international law since 1970, in the form of the nuclear Non-Proliferation Treaty (NPT). The NPT commits its signatories – including the UK – to take steps to disarm if they have nuclear weapons and not to acquire them if they don’t. Frustration by non-nuclear states at nuclear states’ unwillingness to keep their side of the bargain led to a new disarmament initiative, eventually leading to a new treaty supported by 122 countries in a UN vote. It entered into force in 2021, after 50 states had signed and ratified the treaty.

States parties to the TPNW are banned from developing, testing, producing, manufacturing, acquiring, possessing, stockpiling, transferring, using or threatening to use nuclear weapons. It also makes it illegal to assist or encourage anyone to engage in these activities.

Within a year of entry into force, state parties were due to meet to discuss progress with the treaty. Following delays related to the Covid-19 pandemic, the conference will now take place in June 2022.

UK role

The UK government refused to participate in the treaty negotiations and now refuses to sign – or even engage with – the treaty. The UK can sign up prior to disarming if it removes its nuclear weapons from operational status and agrees a transition plan for disarmament.

CND campaign

The UK government continues to state its commitment to multilateral nuclear disarmament and should sign the treaty which aims to achieve that goal.

As a first step, CND is calling on the UK to attend 1MSP as an observer (alongside other NATO states which have declared they will attend). There is no deadline for a government to decide it will attend in this capacity.

Attending the conference would be a first step in engaging with the TPNW and taking concrete steps towards the government’s aim of a world without nuclear weapons.