As opponents to the proposals prepare for a protest outside the SNP conference in Perth, Lord Robertson, a former secretary general of Nato, launched a broadside, calling into question whether or not membership of a nuclear-based alliance would even be open to an independent Scotland, which, under a Nationalist government, would seek to get rid of its nuclear weapons.
"The SNP's camouflage of credibility on defence is fundamentally undermined by the contradictions in their own policy," said the Labour peer, who was also the UK Government's defence secretary.
"They want to remain part of the Nato Alliance while ditching its most important strategic partnership. As part of the UK, Scotland is part of a military which delivers the kind of global reach no small European country can claim. The UK provides Scotland not just with protection but influence," argued Lord Robertson.
"It is perverse to, on the one hand, promote the benefits of collective power at the same time as rejecting the very union from which Scotland's defences most benefit. The real credible change in SNP defence policy would be to remain part of the UK defence alliance but they won't do that."
He added: "Their membership of Nato is uncertain at best. On the one hand, the SNP say they will 'inherit its Treaty obligations with Nato' and, on the other, they remain wedded to unilateralism and neutralism."
Lord Robertson referred to the organisation's Strategic Concept, which says that as long as nuclear weapons exist, Nato will remain a nuclear alliance. "Will the SNP sign up to that, no ifs, no buts, no conditions? I remember negotiating ex-communist countries' entry to Nato and they embraced the Strategic Concept wholesale with none of the ludicrous SNP posturing on show in Perth."
Experts have suggested Scottish denuclearisation, would lead to UK denuclearisation, because it would take at least 20 years to replicate the necessary safety facilities in England to house the nuclear deterrent.
Alex Salmond told delegates: "I trust this conference to act in the best interests of achieving independence."