The Scottish Government is under fresh pressure to unveil its defence plans under independence after new figures revealed the wildly varying size of air forces across Europe.

Even countries roughly the same size as Scotland have vastly different numbers of staff and aircraft, the statistics, compiled by the House of Commons library, show.

It lists just 850 active personnel and 20 planes in the Irish air force. Norway, on the other hand, has more than 3500 regulars and almost 100 aircraft.

Thomas Docherty, the Labour MP and member of the Commons Defence Committee, said it was time for the SNP to "come clean" about its defence plans.

He claimed the threats currently facing Scotland and the SNP's priorities suggested the example the Scottish Defence Force would most closely follow was Ireland.

But Angus Robertson, the SNP's Westminster leader and defence spokesman, hit back, calling on Labour to admit Scotland could match the range of armed services maintained in countries in Northern Europe.

The SNP insists Scotland will have a fully operational defence force and points to the estimated £3 billion Scottish taxpayers currently spend on defence.

The row comes just a week after Alex Salmond said the Scottish Defence Force would operate just one air force base and one naval base.

He was accused of hypocrisy following the Scottish Government attacks on the Coalition Government's plans to cut the number of air bases in Scotland from three to one.

The First Minister's confirmation of the number of bases that could be expected in an independent Scotland has also led to speculation about what size of air force and navy they would house.

The new figures reveal a big difference between countries with very small and medium-sized air forces. Only three countries in Europe have fewer than 1000 active personnel, including Latvia and Lithuania as well as Ireland. However, Norway is then the next smallest, with more than 3500 active staff.

Mr Docherty said: "The SNP need to come clean to the Scottish people about their plans. What we do know is that with no obvious threat on their doorstep and an intention to have a non-interventionist approach then the obvious example is Ireland, which has less than 1000 personnel and fewer than two dozen aircraft.

"The SNP need to specify how many they would have in this and other services."

Mr Robertson insisted Scotland could match the range of armed services maintained by countries in Northern Europe, such as Norway, "all of whom maintain appropriate military capabilities including fast jets, ocean-going vessels and highly trained personnel", he said.

"The reality right now, under the Union, is that the UK Government is leaving only one operating air base in Scotland with at present no helicopters, transport or maritime patrol aircraft."

He added: "Scottish taxpayers have contributed towards these at UK level, and we will ensure that, subject to the appropriate planning, we will have the necessary capabilities based in Scotland."

The SNP has said it will hold a defence review to determine Scotland's needs after independence.

Mr Robertson also took issue with the claim the SNP was "non-interventionist", saying an independent Scotland's priorities would centre on "territorial defence, securing civil power and supporting neighbours, allies and the United Nations".

Both Norway and Ireland are similar in population to Scotland, with almost five million people.

The UK as a whole has 40,000 active personnel, almost 1500 reserves and more than 5000 aircraft.