The former Lord Advocate, Lord Murray, is seeking advice from the current holder of the office, Eilish Angiolini, on the legality of Trident nuclear missiles.

Lord Murray was one of a delegation of campaigners who yesterday made a submission to the Lord Advocate, calling on her to examine evidence that the nuclear deterrent, housed at Faslane naval base on the Clyde, may be illegal under international law.

The campaign group argue that, at the very least, it may be illegal to deploy the weapons in "a state of readiness". This is the position of Lord Murray.

But others in the group, which comprises international law experts, religious leaders and peace campaigners, have gone further, by submitting evidence that even the possession of nuclear weapons may be a criminal act.

The group submits that the Trident nuclear weapon system "violates the law of all the jurisdictions of the UK, including Scotland, insofar as they all recognise relevant aspects of international law. The deployment of Trident can be seen as preparation for a war crime."

By seeking a legal opinion of Ms Angiolini, the group hope to persuade her to make a submission to the UK Government, calling for a full legal inquiry into the status of the missiles system.

Lord Murray, from Edinburgh, said: "Trident tends to be seen as a political issue, but it is also a very important legal issue so let's put aside the politics and have a proper legal debate.

"In my view, the effect of the International Court of Justice's 1996 advisory opinion on nuclear weapons is that as weapons of mass destruction they are prima facie illegal.

"To justify deploying them in a state of readiness a nation must be in extreme danger of imminent attack of genocidal nature. Where is that danger coming from? It's not from Russia or America, far from it."

"In addition, there was an act passed by parliament in 2000 about war crimes which expressly provides that preparation to commit war crimes shall itself be an offence.

"If you take the two into account I think there is a strong case to answer.

"I feel that the Scottish Government should ask the Lord Advocate for her legal opinion on Trident.

"If the Lord Advocate agrees with me, I hope she might do something about it, by making a representation to the UK Government."

He said: "I expressed the view that it is very doubtful whether they were legal. But history shows that I didn't have much success."

Ronald King Murray sat as Labour MP for Edinburgh Leith from 1970 until 1979.

Although the submission is unlikely to provoke any direct response, it will increase the momentum of the campaign to free Scotland of nuclear missiles, which has been transformed in the months since Alex Salmond's SNP came into government.