THE debate inside the SNP on the party's approach to Nato membership heats up today following the formal tabling of the amendment to the controversial conference motion.

At the party's annual conference in Perth in October, Westminster leader and defence spokesman Angus Robertson will propose a controversial U-turn on the SNP's long-standing stance that it would leave Nato after independence.

SNP MSP Jamie Hepburn whose amendment is put in motion today, challenges Mr Robertson's plans to remain in the alliance subject to retaining Scotland's position as a non-nuclear power. He is convinced the mood of the party is in favour of the current position of remaining outside Nato.

Mr Hepburn said: "I am confident that I have today lodged an amendment to the resolution on the question of Nato membership. I have support from a number of colleagues and sides of the party and I look forward to the detail of the debate."

The only votes cast at the SNP conference are those of delegates present but some groups such as trade union and youth supporters are entitled to small numbers of delegates.

Although there is no block voting for these groups, there would appear to be a grassroots rebellion within the party over plans to soften the stance on Nato membership.

Mr Robertson has been in the vanguard of pro-Nato reform, arguing that an independent Scotland could remain within the alliance provided it received guarantees about the nation's non-nuclear stance.

He has come under fire from both sides – from former Nato general-secretary Lord Robertson, who argues this stance would not be permitted, to the CND wing of the SNP who fear backsliding on key issues.

The anti-Nato position was strengthened after the youth wing of the SNP swung behind his amendment on Monday.

Mr Hepburn's amendment states: "Conference recognises that on independence, Scotland will inherit its membership of Nato, and that it will be for the Scottish people to decide whether to retain membership.

"As Nato continues to be a nuclear weapons based alliance, Conference resolves that the SNP position will continue to be that Scotland should not remain a member of Nato, but instead co-operate as part of the Partnership for Peace programme and be a full member of the Common Security and Defence Policy of the European Union."