THOUSANDS of defence jobs will be lost in an independent Scotland as firms downsize or pull out altogether, a leading industry expert claims in a scathing report.

Helicopter contractors and suppliers could cut their operations or withdraw altogether, and a lack of SNP planning for military resources is creating "a dangerous void", according to defence analyst Francis Tusa.

Alex Salmond wants a Scottish Defence Force (SDF) to consist of armed forces with an air base, naval base – without nuclear submarines – and a mobile armed brigade.

The report in the respected journal Defence Analysis, which Mr Tusa edits, also suggests the model for an independent force would be the more modest resources of Ireland, not the complex capabilities of countries like Norway.

It pours cold water on the First Minister's claim that soldiers would want to leave the UK forces to join a Scottish Defence Force.

Jim Murphy, Labour's Shadow Defence Secretary, said the report's conclusions were "very damaging" for the Scottish Government.

The SNP said the report made "mistaken assumptions", and it rejected the idea Scotland would not have the same military capabilities as Norway after independence.

A spokesman said the £3 billion Scotland currently contributes to defence spending meant there was "no doubt" that it could easily match the fast jets, ocean-going vessels and highly-trained personnel of its Northern European neighbour.

The report is the latest of a number of warnings about what an SDF might look like.

Ex-Labour security minister Lord West, the former head of the Navy, recently suggested an independent Scotland could not afford to run some types of expensive military equipment even if it was given to them in the "divorce" from the UK.

Mr Tusa suggests the effects on the defence industry, which supports thousands of jobs in Scotland, could be catastrophic.

The SNP's approach, including its stance on Nato, suggests an independent Scotland "does not look like a country that will have the need for either large or complex armed forces", it concludes. It adds: "If stated SNP policy about the future of Scottish forces is to be taken as gospel, then Belgium and Ireland are far more realistic models for Edinburgh than Norway or Denmark".

As such, any SDF would not need the same range or sophistication of equipment as the UK's armed forces, the report says.

Tens of thousands of jobs across Scotland depend directly or indirectly on defence, including many shipbuilding jobs.

But the knock-on effect of the SNP's plans would be to "support a far smaller work force", the report warns.

Local industry will become "simple and ... cheap", with shipbuilders constructing smaller offshore patrol vessels instead of large-scale cruisers.

Facilities could well close, the report also says, including the Vector Aerospace helicopter maintenance facility at Almondbank in Perthshire.

It queried whether Edinburgh-based Selex Galileo, which supplies electronics, would keep a full range of capabilities north of the Border.

It suggests the new army would only have two or three brigadiers and perhaps a major- general, adding "wouldn't this persuade ambitious Scottish troops to stay with the larger British armed forces?"

The report also rounds on the SNP claiming the "lack of any detailed planning or options (on defence) is a dangerous void".

The analysis updates a similar report from 2007.

The SNP said: "If we want real examples of the defence landscape ... we only need to look to our Northern European neighbours of comparable size, all of whom maintain appropriate military capabilities," a spokesman said. He added that the earlier report had made mistaken assumptions about Scotland's population, tax revenue and gross domestic product and said the latest report seemed "equally unsound"

Mr Murphy claimed it was "peculiar" that the SNP relied "on a catch-all comparison that says that defence in a separate Scotland will be like Denmark and Norway" when both nations had actively contributed to major Nato operations including in Afghanistan.