NO-ONE, on either side of the debate, is suggesting that an independent Scotland would not be welcomed by the European Union.

The real question is, on what terms?

And there lies the SNP's problem. Until recently, at least, it has denied there was any question at all over the terms of membership, accusing anyone who dared suggest otherwise of scaremongering.

Alex Salmond's Government claimed in three key documents – most recently Your Scotland, Your Referendum in January –that an independent Scotland would continue in EU membership.

Ministers insisted Scotland would inherit the same treaty rights and obligations as the rest of the UK, including a share of Britain's cash rebate and its opt-outs from the euro single currency and Schengen free travel area, which has removed border controls between most members.

But recently their position has shifted in the face of growing evidence that the reality was far less clear cut.

In October, the First Minister publicly acknowledged that negotiations would be required but suggested talks would touch on minor issues, such as the number of MEPs Scotland would send to the European Parliament.

Now the SNP claims it "always said" the specific terms of Scotland's EU membership would be negotiated.

Deputy First Minister Nicola Sturgeon has requested formal legal advice on the issue from the Lord Advocate and yesterday announced she was seeking talks with the EC to discuss the Government's plans for independence.

A few months ago, such action was deemed unnecessary because the position was supposedly crystal clear.

The SNP's consistent argument has been that a newly independent Scotland and the rest of the UK would enjoy exactly the same legal status in relation to the EU.

That was always considered fanciful by the Nationalists' opponents.

Now it is beginning to look less a statement of fact and more a negotiating position – what Scottish Government officials would tell their Brussels counterparts the day after a Yes vote – in the light of Jose Manuel Barroso's comments.

"Yes Minister" Ms Sturgeon knows the Government's claims on EU membership are causing damage.

The prospect of negotiations throws up legitimate questions about pressure to join the euro or the Schengen agreement, which the UK Government claims could lead to border checks at Gretna.

In addition, the SNP has been made to look as if it has had something to hide. Opposition politicians are again questioning Mr Salmond's trustworthiness, only a couple of months after he was accused of misleading the public over the existence of legal advice on EU membership.

Ms Sturgeon will hope her proposed Brussels talks will clear up the confusion and allow her to concentrate on the contribution an independent Scotland could make to the EU and the benefits it would derive.

Blogging on the Scottish Constitutional Futures Forum, Edinburgh University academic Professor Neil Walker said both sides in the debate were guilty of presenting their arguments on EU membership in "unhelpfully black and white terms".

He concluded that, regardless of whether Scotland was treated as an existing EU member or brand new applicant, substantial negotiations would be needed on the euro single currency, budget contributions and a wide range of other issues.

He warned of tough choices and difficult compromises.

However, he felt it unlikely that an independent Scotland would join the EU on significantly less favourable terms than the country enjoys as part of the UK.

There would be some tough talks, was his message, but they would take place in a "spirit of reasonable mutual accommodation".