Independent Scotland could be €4.5bn worse off in EU

"On the terms of the White Paper alone, they are offering a fraction of what Scotland already has and at a higher price," he added.

Treasury minister Danny Alexander, whose constituency is in the Scottish highlands, noted that Scotland was between £1.9 billion and £3.8 billion better off in Europe as part of the UK.

"Leaving the United Kingdom we would see our international influence decrease and we would see the costs to our country increase," he said.

Unsurprisingly, the UK government's lawyers assert that Scotland would have to re-apply to join the EU if it voted for independence.

"As a new state, an independent Scotland would have to apply for membership of the international institutions. In some cases this would straightforward; in others, notably the EU, it would not," the paper warns.

In an interview with BBC Scotland, Hague said that Scots "should be in no doubt" that an independent Scotland would have to reapply for European Union membership.

According to analysis from Westminster, Scotland would also have to contribute to the EU budget without being entitled to any of the UK's £3.1 billion (€3.7 billion) per year rebate, although it does suggest that it would receive extra farm subsidies worth £850 million (€1 billion) from the bloc's common agricultural policy.

Scotland will vote on whether to leave the UK in September 2014.

The Scottish government estimates that it would then take eighteen months to negotiate the status of its independence from the UK and its continuing membership of the EU. But Alex Salmond, who leads the Scottish government, claims that the country would be able to renegotiate its status from within the 28-country bloc.

For her part, deputy first minister Nicola Sturgeon hit back, suggesting that plans by David Cameron to renegotiate Britain's EU membership was a greater threat to Scotland's place in the EU.

"Nothing we propose changes the material conditions of any other member state - while they are so certain of complete success in their own ill-advised re-negotiations with the EU," he said.