Angus Robertson MP will tell the party conference in Inverness that the two newly separated nations would remain "friends and allies", so it would be "perfectly possible" to "share basing, procurement and training facilities with the rest of the present UK", even after Scotland had become a sovereign state.
The proposals appear to suggest that RAF bases, such as those at Leuchars and Lossiemouth, could be shared between Scottish and English fighter jets. It also opens up the idea of Scottish-based garrisons, such as Redford Barracks in Edinburgh and Fort George in Inverness, containing soldiers from both nations' armies. It may also mean that 45 Commando Royal Marines may be retained at its Arbroath base.
However, Robertson also says that an independent Scotland would reserve the right to "stand aside" from wars to which it was opposed. In recent years, the SNP has refused to support the war in Iraq and the Nato invasion of Kosovo.
He also asserts that an independent Scotland would have the right to remove Trident submarines from Scottish waters.
The plans were described as "complete fantasy" last night by Labour, which said the British government would have little desire to invest in a post-independent Scotland. The Conservatives claimed Robertson's plans had exposed how an independent Scotland would be entirely dependent on English co-operation for survival.
Meanwhile, military experts warned that Scotland would end up having to pay the former UK government to keep its facilities in Scotland.
But the SNP argues that its sharing plan showed that the "supposed disbenefits" of independence for the nation's defence was a "chimera".
Writing in today's paper in advance of giving The Scotland on Sunday Lecture at the SNP conference, Robertson argues: "On the basis of mutual interest, it is perfectly possible to envisage circumstances in which we share basing, procurement and training facilities with the rest of the present UK – our foremost friend and ally under all constitutional arrangements – in exactly the same way as defence co-operation exists across the Scandinavian nations."
Robertson is calling for a specific Scottish Defence Review, to go alongside the British Defence Review, to ensure that the country's defence policy "reflects Scotland's priorities and preferences". The SNP argues that a review would probably conclude that most Scots were opposed to the UK defence policy, including its policy of keeping Trident on the Clyde.
Robertson says that independence would ensure that Scotland would be able "to choose which theatres to be involved in".
Independence would also allow an SNP-led government to remove Trident from Scotland, he continues. "No independent nation of five million has nuclear weapons, and nor should we," he declares.
The SNP's plans for defence come as the party prepares to head to Inverness on Thursday for its annual conference, where it will increase calls for an independence referendum.
In an interview yesterday, First Minister Alex Salmond said his aim for next year's general election was to gain enough MPs to hold the balance of power in what many expect to be a hung parliament.
"There's a vast overwhelming majority of people in Scotland, regardless of political preference, who rather like the idea of the Westminster parliament being hung by a Scottish rope," he said.
Scottish Secretary Jim Murphy last night unveiled Labour's election campaign theme, which will claim that a vote for the SNP helps to install the Conservatives at Westminster. He said: "Labour's campaign – Vote SNP, Get Tory – will put this issue centre stage between now and the general election."
As for Robertson's proposals, military experts said last night that, while it would be feasible to imagine a sharing arrangement post-independence, there would be complications as well.
Colonel Bob Stewart, the former United Nations commander in Bosnia, said: "There would have to be a State of Forces Agreement such as there is between the UK and Germany (where British troops are currently garrisoned). In theory, it is possible for this to happen, but there are complications. Would Scotland be part of Nato, for example?"
He added: "It would all come down to money. If you wanted to keep English troops and bases here, how much would you be prepared to pay? The Germans don't want us to withdraw because British troops there substantially subsidise the local economy."
However, shadow Secretary of State for Scotland David Mundell said: "An independent Scotland would have to rely on England's goodwill on defence and security."
He added: "Alex Salmond can't expect to break up Britain and have the rest of the United Kingdom dance to his tune. His defence policy doesn't stack up. It is fooling nobody and would threaten tens of thousands of jobs in Scotland. Alex Salmond needs to get on with his job in the Scottish Parliament, because he just can't cut it on the wider stage."
Meanwhile, a senior Scotland Office official described the proposals as "complete fantasy", claiming that after independence the government south of the border would have no incentive to invest or be sited in a foreign country such as Scotland.
The source said: "Shipbuilding on the Clyde would go – the Royal Navy would not give contracts to a foreign country. This would be another hammer blow to Glasgow from the nationalists. In all, 20,000 defence-related jobs would be at risk. In Morayshire, 2,000 jobs would go – no Trident, no Nimrod, no Kinloss."
As for the plans to scrap Trident, the source added: "In a world in which rogue nations are seeking nuclear weapons, it is madness for the SNP to suggest that Scotland should be defenceless. The majority of Scots have consistently rejected the policies of pacifism and one-sided disarmament set out by Angus Robertson."