A BRIEF to parliamentary colleagues by SNP defence spokesman Angus Robertson justifying his proposal that Scotland should remain in Nato has come under heavy fire from the party's CND wing.

They claim inaccuracies and omissions in the brief mean his case falls apart, particularly in relation to the Arctic, where they say Nato is divided and has no united policy.

Mr Robertson says the party should switch from a policy of joining Nato sub-group Partnership for Peace (PfP) and remain in Nato, subject to a deal that Trident is removed from the Clyde.

Mr Robertson travelled in Norway, Denmark, Iceland and other countries, taking soundings from ministers, parliamentarians and defence experts before drafting his new policy.

He writes in his briefing paper, circulated ahead of the debate in a fortnight: "Scotland's geostrategic interests in northern Europe are shared by our North Sea neighbours, all of whom are in Nato. At present our security arrangements, including air and sea defence and patrolling are through Nato.

"Regional challenges are urgently set to grow with environmental changes in the High North and Arctic. In short, we need to work with our North Sea Nato neighbours more than ever."

A rival briefing paper from SNP CND points out that the Arctic Council, not Nato, is the recognised body responsible for security in the "High North" and as a result of splits within Nato – with Canada disagreeing with both the US and Norway on their approach – the Arctic does not feature in current strategy.

Bill Ramsay of SNP CND said: "While not questioning the sincerity of Angus Robertson's opposition to nuclear weapons, the more you examine his justification for a Nato U-turn, the more the case falls apart.

"His briefing paper is full of inaccuracies, omissions and a misunderstanding of geo-politics, especially in relation to the Arctic. The world is looking to Scotland. We deserve a well-informed and considered security and foreign policy, not this."

Mr Robertson is accused of referring to "North Sea" Nato members without acknowledging that Finland and Sweden are PfP members not in Nato.

Mr Robertson said: "I am looking forward to a quality debate on the SNP's defence policy update at conference – including reaffirming our long-standing commitment to get rid of Trident. I know from speaking to members of other parties that they are jealous of a party which still takes major issues to conference "