THE SNP have come under fire after a senior party figure suggested a Scotland could temporarily host the UK’s nuclear weapons after independence.

Stewart McDonald has been accused of betraying a commitment he made as a signatory of a radical anti-bomb pledge.

In a letter to The National, the Scottish liaison for the International Campaign to Abolish Nuclear Weapons (ICAN), Janet Fenton said the SNP’s defence spokesman’s comments were “incompatible” with the vow he had taken as a signatory to its Parliamentarian Pledge for the Treaty on the Abolition of Nuclear Weapons.

McDonald told the BBC on Wednesday Scotland post-independence would join Nato on “similar terms to those of Norway, of Denmark in that we don’t want to permanently host nuclear weapons from other states”.

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He added: “We certainly will take our commitments as new members of the alliance seriously.

“I don’t think anyone’s suggesting that an independent Scotland should permanently be host to another state’s nuclear weapons.”

But a key plank of the pledge McDonald signed included a commitment to campaign against “any stationing, installation or deployment of any nuclear weapons or other nuclear explosive devices in its territory or at any place under its jurisdiction or control”.

Fenton said McDonald’s comments put him at odds with the treaty and said it could have severe political ramifications for the SNP’s support.

She said the party’s “strong anti-nuclear message is at the heart of its continued support over many years” but warned moving an inch on its commitment to ban weapons of mass destruction could see its votes “haemorrhage like snow off a dyke”.

Fenton appeared to take issue with the SNP’s stance on Nato more generally, stating the organisation was a “a military alliance with, for the moment, a nuclear armed policy”.

The Scottish Greens, Fenton noted, remained opposed to Nato, unlike the SNP, which began supporting the alliance in 2012.

She wrote: “The Greens’ position is not obfuscated by any confusion about Nato.”

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The controversy stems from the question of whether Scotland would be admitted to Nato should it remove Britain’s atomic bombs from its waters after declaring independence.

Sweden and Finland, two non-nuclear states, are currently seeking Nato membership and have been promised speedy entry to the alliance by its secretary-general despite not possessing weapons of mass destruction.

Speaking with The National earlier this week, McDonald emphasised that while Scotland would be applying for membership post-independence from a different position to the two Nordic nations, the Nato leader’s comments were encouraging for the SNP’s position.

He said: “It is good for us because it makes the argument smoother.

“As background music, if I can call it that, it’s good for us but I think there is more for us to take from this rather than just the issue of nuclear.”

McDonald has repeatedly made the argument that bringing a military speciality, for instance expertise in battlefield medicine, could boost Scotland’s case for joining Nato after independence.

Responding to Fenton’s comments, the SNP MP said: “There has been no change in the position we have held for many years and that which was in the white paper in 2014.”

McDonald was told in the Commons on Thursday the SNP's position on nuclear weapons was "beyond credibility". 

During a general debate on Nato, veteran Tory MP Bernard Jenkin said the SNP's opposition to Trident "devalued" McDonald's contributions. 

He added: "Because Scotland by far the greatest contribution that Scotland makes to the defense of Europe is the hosting of the nuclear deterrent, and the idea that this will be uprooted by an independent Scotland, and that Scotland would then present itself as a good member of NATO is utterly ridiculous."