An SNP proposal which would see an independent Scotland allow English soldiers, sailors and airmen to continue being based north of the border has been described as a “fantasy” by the party’s opponents.

The plan will be floated at this week’s SNP conference in Inverness and is an attempt to head off predictions that if Scotland separated from the rest of the UK, thousands of defence jobs would go and military bases would be withdrawn.

Angus Robertson, the SNP defence spokesman at Westminster and the MP for Moray, which houses two RAF bases, will portray the invitation to the military to stay as an example of an independent Scotland wanting to remain “friends and allies “ with what remains of the UK post-Scottish independence.

Labour critics attacked Mr Roberston’s plan as “complete fantasy” and Conservatives said that it provided proof that an independent Scotland would have to rely on England’s goodwill for security and protection.

Mr Robertson also appeared to catch some of his SNP colleagues by surprise. Nicola Sturgeon, the party’s deputy leader and the Deputy First Minister, said that he had been merely “talking about a principle.” She added: “There would have to be a great deal of negotiations and discussions.”

Mr Robertson, writing in a Sunday newspaper, called for a Scottish defence review to ensure that defence policy reflects Scotland’s priorities and preferences. He said that currently Scottish taxpayers are “disproportionately” contributing huge sums towards the UK Ministry of Defence, while the UK’s “defence footprint” north of the border is declining.

He argued that a review would demonstrate the benefits of independence, such as being able to decide which operations to be involved in.

He wrote: “Like other small independent nations, wherever and whenever we did wish to take part in conflict or peacekeeping roles, we could do so in partnership with our friends and allies. And where we judged the use of force to be not justified, we would have the ability to stand aside.”

Mr Robertson’s proposals appear to suggest that RAF bases such as those at Leuchars and Lossiemouth would stay, Army garrisons such as Fort George and Redford in Edinburgh would house both Scottish and English soldiers and 45 Commando Royal Marines would continue to be based at Arbroath.

However, the welcome would not be extended to the Royal Navy’s Trident nuclear submarine base on the Clyde which, after independence, would have to be moved out of Scotland to comply with a key anti-nuclear policy of the Nationalists.

Des Browne, the former Defence Secretary in the UK Government, claimed that Mr Robertson’s plans meant that he wanted Scotland to be “just be a big military base for the remainder of the UK”.

He said: “In coming up with this latest suggestion, Mr Robertson has admitted that the SNP have no idea how to raise the forces necessary to defend Scotland. In the absence of any policy, they simply want the rest of the UK to do it for them.

Times Recommends

• Fern Britton: 'I still can't see that I was wrong'
• Extreme cooking
• Easy French: Tarte Tatin