AN independent Scotland's defence forces would not be at full strength for a generation, MPs have been warned.

Three leading defence experts yesterday claimed the nation could be drawn into a possible conflict in the Arctic following increasing levels of Russian activity in the area.

Other European countries were investing in defence amid such fears, defence analyst Francis Tusa told the Commons Scottish Affairs Committee.

Malcolm Chalmers, from the Royal United Services Institute, suggested it would take 20 or 30 years to get Scottish defence forces up to "ideal" levels.

Hew Strachan, from Oxford University, said an independent Scotland would struggle to keep its infantry battalions up to strength as Scots would "vote with their feet" and join the British Army instead for better career prospects.

Mr Tusa, editor of the journal Defence Analysis, agreed, telling MPs an unofficial opinion poll among soldiers he had undertaken revealed the majority had said they would stay with the British Armed Forces.

He also warned the defence industry would "follow the money" and companies would leave Scotland for England within months of it breaking away from the rest of the UK.

The warnings came as the Prime Minister confirmed that Scotland's historic regimental names such as the Black Watch are safe. However, the threat remains that at least one of the five battalions of the Royal Regiment of Scotland could be lost in an Army shake-up. One suggestion is the historic name of any scrapped battalion will be transferred to one of Scotland's two TA battalions.

Labour, the Liberal Democrats and the SNP have joined forces at Westminster to launch a "respect our regiments" campaign to fight any cuts.

In the Commons, David Cameron told Labour's Jim McGovern it was very important to keep the regimental structure.

He said: "Obviously though, at the same time, we need to deliver this big change in our armed forces, which is not going to deliver a larger army but a better balance between a professional army and a territorial army.

"We are looking at exactly how that can be done while saving the important regiments that people, like me too, feel so strongly about."

Earlier this month, The Herald revealed Coalition sources had made clear Mr Cameron was not convinced by proposals being drawn up by Defence Secretary Philip Hammond, stressing there were no plans to adopt a continental-style system, replacing names with numbers.

Yesterday, a Westminster debate on Scotland's military led by Pete Wishart, the SNP MP for Perth, heard Nick Harvey, the Armed Forces Minister, say there had been a "misrepresentation" of the Government's plans. He told MPs there was "not any intention to remove from the battalions of the Royal Regiment of Scotland the historic names that form an important part of the Army's heritage".

Last night, Mr Wishart gave a guarded welcome to Mr Harvey's remarks, saying: "What we have to do is get further clarification on this.

"What has to be maintained is the golden thread of historic attachment to regiments and their local areas."

This was echoed by Labour's Russell Brown, who said that Scotland's service personnel had been treated in a "callous way and now deserve total clarity on the Government's intentions".