THE US government plunged deeper yesterday into the row over whether to replace the submarines that carry the ­Trident nuclear missile, ­reiterating its support for ­Britain’s atomic arsenal.

Westminster is preparing to replace its fleet of Vanguard-class nuclear submarines, based at Faslane on the river Clyde, with new vessels to be jointly developed with Washington to carry the existing US-manufactured Trident D5 missile.

The intervention, after the Scottish Parliament voted overwhelmingly on Tuesday to call for the scrapping of the Successor programme, recognises the growing opposition to atomic weapons.

Scottish Labour adopted a similar position to the Scottish National Party at its annual conference last weekend, opposing British-based nuclear weapons but maintaining its support for nuclear-armed military alliance Nato.

Following the vote, US State Department spokeswoman Julia Mason said: “We defer to the UK government on questions regarding UK domestic affairs and its national defence.”

But she immediately added: “We value the UK’s role as a strong Nato ally and its contribution to Nato’s nuclear deterrent.”

Campaign for Nuclear Disarmament general secretary Kate Hudson told the Star: “It’s good to hear that the US State Department defers to the UK government on matters of national defence and they must be kept to that commitment.

“It would be wholly unacceptable if the US attempted to intervene in the decision about Trident replacement, which is absolutely a matter for the British people alone to decide.

“Britain must determine its own answers to its own security needs.”