THE bid to stop a change to the SNP's historic anti-Nato policy is set to intensify, with campaigners insisting they want to start a "grassroots movement" to defy Alex Salmond and the party leadership.

A meeting of the Nationalists' Campaign for Nuclear Disarmament group in Glasgow yesterday aimed to "educate" SNP members about what the proposed U-turn in policy could mean for the party and to its chances of securing a "yes" vote in the Scottish referendum on independence in 2014.

Opponents of the change believe it would "make the SNP look cynical and lacking in moral courage".

Gareth Finn, SNP CND group convener, said the turnout at the seminar – about 65 people, including MSPs John Finnie, Dave Thompson, Jean Urquhart, Sandra White and John Wilson – was impressive.

"The next step is for members to go back to their SNP branches with that information and pass it around. We want to expand the debate to a grassroots movement rather than just discussing it in the hierarchy of the party."

He added: "The main issue is that Nato is a nuclear alliance and it doesn't fit in with our vision for Scotland. We are a prosperous and outward-looking country, I don't see why we need to be part of the alliance because I don't see any threat to Scotland.

"It's a challenge for those seeking to change party policy to inform us of where they see these threats coming from."

Ten of the SNP's 67 MSPs have so far come out against the leadership's proposal, which is being strongly promoted by Angus Robertson, defence spokesman and leader at Westminster.

One of the opponents of the proposed policy change, Dave Thompson, MSP for Skye, Lochaber and Badenoch, said: "We're better with our current policy because it's the right policy.

"You would need to ask Angus whether he thinks his policy is the right policy or is he purely following opinion polls – that's not for me to say. He's got to come up with sound reasons."

In a briefing paper circulated this week, the Nationalists' CND group argued that changing policy could lose the SNP support and did not guarantee extra votes for independence.

It argued: "It confuses the strategy and makes the SNP look cynical and lacking in moral courage. It alienates almost all active supporters of independence outside the SNP and will cause more conflict within the Yes campaign.

"It removes all differentiation between the SNP and the other parties. It does nothing to counter the media onslaught from those that oppose independence.

"In fact, tactically and strategically, it is hard to see what meaningful benefit it is meant to bring."

However, the leadership has held up a University of Strathclyde poll carried out in May, which found 52% of SNP members surveyed wanted to remain in Nato.

"With an agreement to withdraw Trident from Scotland, we should be willing to work with our neighbours and allies," insisted Mr Robertson.

The contentious proposals are due to be debated at the SNP party conference in October.

Ruth Davidson, the Scottish Conservative leader, said: "The ridiculed Nato stance is only one small element of SNP defence policy that is exceptionally weak."