IN a car crash of an interview with the BBC, Stewart McDonald appears to have allowed the dog to have eaten his homework.

His weird remarks are incompatible with the commitment he made when he signed the Parliamentarian Pledge for the Treaty on the Prohibition of Nuclear Weapons (TPNW).

It reads: “As parliamentarians, we pledge to work for the signature and ratification of this landmark treaty by our respective countries, as we consider the abolition of nuclear weapons to be a global public good of the highest order and an essential step to promote the security and well-being of all peoples.”

We assume that they all read the treaty and understood its comprehensive and absolute prohibitions.

The International Campaign to abolish Nuclear Weapons (ICAN) was awarded the Nobel Peace Prize for its contribution to the UN adoption of the TPNW in 2017.

The same year that McDonald signed up to the pledge, along with every elected parliamentarian in the SNP and also every elected Scottish Green.

Of course the Greens’ position is not obfuscated by any confusion about Nato. That year our First Minister declared to a party conference: “No ifs, no buts, no nuclear weapons on the Clyde – or anywhere.”

So it appears that Stewart McDonald’s dog has also eaten his copy of his own party’s manifesto as well as his copy of the TPNW, with its absolute prohibition in: “Article 1 (e) Assist, encourage or induce, in any way, anyone to engage in any activity prohibited to a State Party under this Treaty; and Article 1 (g) Allow 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.

The perfect storm is Scottish independence and accession to the TPNW, understood by Nicola Sturgeon when she endorsed The Scottish Women’s Covenant in support of the treaty with this message.

“While the Scottish Government is unable to become a party to the treaty, as First Minister I strongly support the principles of the treaty and the work of the Women’s International League for Peace and Freedom. An independent Scotland would be a keen signatory and I hope the day we can do that is not far off,” she said.

The SNP’s strong anti-nuclear message is at the heart of its continued support over many years. And while many hoped that the referendum would give us the power for disarmament, in 2014 the TPNW was still a dream, leaving the fear of the UK strong arming Scotland into nuclear compliance.

SNP membership and support could haemorrhage like snow off a dyke if the electorate were to suspect that any caucus sought to abandon the policy at this juncture, with the possibility of a nuclear-free independent Scotland in sight.

Maybe Stewart McDonald’s dog has not been in at any Nato briefings as well, if he does not understand that Nato is a military alliance with, for the moment, a nuclear armed policy.

Nuclear weapons are not mentioned in the North Atlantic Treaty, and whether Nato maintains the current policy in light of the TPNW’s progress (with another ratification yesterday there are now 61 UN member states) will be a topic for discussion.

Some of the Nato states are, unlike the UK’s Government, attending the TPNW First Meeting of States Parties in Vienna next month.

Janet Fenton is the vice-chair of Scottish CND and Scottish Liaison for ICAN