Today the United Nations’s nuclear weapons ban treaty opens for signature. States across the world are queuing in New York to sign up to prohibit nuclear weapons. This is a giant step forward on the road towards global abolition.

The treaty follows decades of grassroots campaigning across the world — the Campaign for Nuclear Disarmament (CND) has been calling for a global ban on nuclear weapons since its founding in 1958 and we are delighted at the development.

Over 100 countries are likely to sign the treaty, but will Britain make the most of this crucial opportunity for peace?

At the moment — under this Tory government — things aren’t looking too positive. When the ban treaty was negotiated, our government boycotted the process, despite claiming that it plays a full and active role in the UN’s disarmament discussions.

As the first round of talks got underway the British ambassador chose to stand shoulder to shoulder with the US ambassador as she denounced the efforts to bring about a nuclear-free world.

Successive British governments have stated their support for multilateral nuclear disarmament, but they have failed to take action to match the rhetoric.

Our job now is to exert pressure on the government to back it — rather than its current position, which is that Britain will never support it.

Of course, it’s not just a question of this government’s policy. The next prime minister may well be Jeremy Corbyn and it is vital that the Labour Party backs the ban treaty as well as shifting its policy on Trident.

This should be helped by the TUC’s new policy, passed at its recent Congress, which calls on Labour to set up a shadow Defence Diversification Agency while still in opposition.

This would help develop a national industrial strategy including the conversion of defence capacity, with workers, trade unions and local authorities, “so that practical plans can be drawn up for arms conversion while protecting skilled employment and pay levels.”

As we head towards Labour Party conference this weekend, it is vital that the question of nuclear weapons and Britain’s possession of them, remains on the political agenda.

Of course it’s a question of money — surely Labour won’t waste £205 billion on weapons of mass destruction when that money can be invested in social provision, health, housing and hundreds of thousands of sustainable industrial jobs?

But it’s not just the money. It’s also about how we get to a safer, more just world. There are many in Labour who want Britain to play a new role in the world, not the neocolonial, US-poodle role that we are currently playing.

Labour in government must bring about that change. Breaking from Trident and backing the global ban is an essential part of that.

Britain cannot play a different role in the world while it remains part of a tiny minority of countries with nuclear weapons — at odds with the overwhelming majority of states which demand global nuclear disarmament.

Of course, we know why some in Labour back nuclear weapons — Tony Blair said it all in his autobiography when writing about Trident replacement.

He said there was a good case both for and against Trident, but in the end he decided it should be replaced because not to do so would be too great a downgrading of Britain’s status as a nation.

Surely Labour has now moved on from this? Corbyn’s vision for Britain — backed by hundreds of thousands of new members and supporters — has nothing in common with Blair’s perspective.

And just in case anyone in the Labour establishment is thinking that the party needs to back Trident and nuclear weapons for votes, then think again. Times have moved on, and polls show that the majority, particularly among young voters, are opposed to nuclear weapons.

When you have this debate in public meetings or on street stalls, some people will say that getting rid of Trident won’t solve the problem of nuclear weapons elsewhere in the world.

Yes: it’s true that Trident is a relatively small part of a massive global problem that needs to be dealt with. But that’s where the UN’s nuclear ban treaty comes in.

For many years we have argued that nuclear weapons must be banned in the same way that chemical and biological weapons have been banned — or more recently cluster munitions and landmines have been outlawed.

This new treaty fits the bill. In short, it’s a comprehensive ban on nuclear weapons, prohibiting their use, stockpiling, testing, production, manufacture, stationing and installation.

Importantly, it also bans assisting with prohibited acts, such as the United States leasing the Trident missiles to Britain to carry nuclear warheads.

States are encouraged to join the treaty as soon as possible, but there are provisions for joining at a later stage. The treaty makes it possible for Britain to sign up while submitting plans for eventual disarmament and this is what the Labour Party should be preparing to do.

The Tory government’s insistence that Britain will never sign has to be vigorously rejected.

And side by side with Labour’s shadow Defence Diversification Agency, let’s see Labour breaking with Tory policy and developing its own plan for disarmament, responding to Britain’s genuine security needs, shaping its new role in the world, within the framework of the United Nations global nuclear ban treaty.

Please help bring about this change. Visit CND’s website for campaigning actions on Trident replacement and the global ban treaty.

Kate Hudson is CND general secretary. Visit cnduk.org to join CND’s actions in support of the nuclear weapons ban negotiations.