AN SNP MP has blasted UK Government plans to spend billions on nuclear warheads to replace Trident.

Stewart McDonald, the party’s defence spokesman, has also demanded that the UK defence minister come before Parliament today to issue an urgent statement on the matter.

The details about the nuclear replacement plan emerged in the US before Westminster politicians had been informed and suggested that the warhead will be based on US technology.

The Ministry of Defence then confirmed that officials were working towards the replacement, but had not been able to find the time to inform Parliament, adding that an update would be given “in due course”.

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Its update to Holyrood published shortly before Christmas did not confirm the upgrade, stating instead that “work also continues to develop the evidence to support a Government decision when replacing the warhead”.

US Strategic Command chief, Admiral Charles Richard, said in a statement last week a replacement warhead, called W93 or Mk7, was needed in the US.

He added: “This effort will also support a parallel replacement warhead programme in the United Kingdom whose nuclear deterrent plays an absolutely vital role in Nato’s overall defence posture.”

The plans were also referenced by the Pentagon’s Under Secretary of Defence Alan Shaffer who said “it’s wonderful that the UK is working on a new warhead at the same time”, according to the US publication Defense Daily last week.

Glasgow South MP Stewart McDonald said: “This is a quite astonishing story. Not only are we learning about a new UK nuclear missiles programme from the US Senate but the programme itself clearly sets the UK on course to breach the Non-Proliferation Treaty, to which it is a signatory.”

The treaty aims to prevent the spread of nuclear weapons and work towards the goal of nuclear disarmament, and complete disarmament.

Mr McDonald added that the programme “rips up” the treaty’s commitment to stop the nuclear arms race, and said: “That is of utmost concern. Matters of defence and security are the first job of government – it therefore stands that they are the first job of parliament as a scrutinising and legislating body.

“Why are we learning that the UK Government is gearing up to renege on its own international commitments, to the tune of billions of pounds, from the US Senate and not the UK Parliament? The defence secretary must come before parliament tomorrow.

“In 2018, Theresa May gave a speech at the UN in which she described the Nuclear Non-Proliferation Treaty as ‘the flagship of the international community’s determination against nuclear proliferation’. In that description she was right. Her successor now seems to want to walk away from that.”

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Boris Johnson has long backed the proposed replacement and the Conservatives committed to renewing the deterrent ahead of the election, at a cost of £31 billion.

An MoD spokeswoman said: “As previously stated in the 2015 defence review, we can confirm that we are working towards replacing the warhead.

“We have a strong defence relationship with the US and will continue to remain compatible with the US Trident missile.

“An announcement about the UK’s replacement warhead programme will be made in due course.”