The warning from the president of the European commission, José Manuel Barroso, that an application by an independent Scotland to join the European Union would be "difficult if not impossible" to negotiate is both politically maladroit and unlikely to improve Barrosso's lamentable record in running the EU's executive for the past 10 years as he now prepares to leave office.

In seeking to frighten Scottish voters with dire predictions that the Spanish government might veto any Scottish EU membership application, he was, of course, merely mimicking identical declarations by David Cameron and the main Scottish unionist leaders. They have all stressed that Madrid would probably block Scotland for fear that otherwise the growing movement for Catalan independence would become irresistible.

But the language being used by the Spanish government does not support these dire predictions. In a recent interview the Spanish foreign minister, José Manuel Garcia-Margallo, stated that a Scottish EU application should be considered in the event of a Yes victory in the referendum. He went on to insist: "If Britain's constitutional order allows – and it seems that it does – Scotland to choose independence, we have nothing to say about this."

More strikingly he went out of his way to distance himself from suggestions that the Scottish and Catalan cases were inseparable for Madrid. "The two issues are 'fundamentally different'," he declared.

Of course, a referendum victory for Scottish independence would have to be followed by detailed negotiations on a host of practical issues between Edinburgh and London, and between both Edinburgh and London and Brussels. But suggestions that these negotiations might stretch into the indefinite future are baseless. Scotland has already accepted a mountain of detailed EU law as part of the UK.

Two issues which require sensitive handling are fishing policy – where Edinburgh may seek some adjustments in the current regime – and, more importantly, whether and in what form it should be committed to eventual membership of the euro. Most insiders in Brussels believe there is little reason to doubt that negotiations could be wrapped up in about two years after the referendum if the Yes campaign emerges victorious.

It cannot be stressed too often that there is no provision in EU law for, in the meanwhile, depriving Scottish EU citizens of their existing rights as EU citizens. Such a step can in EU law can only be contemplated when an existing member state has been legally shown to have committed serious violations of European democratic or human rights provisions.

In the hullabaloo created by English Tory and Scottish unionist politicians, one critical question has been overlooked. Without Scotland could the present UK state be regarded it as the same state it was? A United Kingdom of England, Scotland, Wales and Northern Ireland it would no longer be. If so, why should the status of the "rump UK" be any different to that of Scotland?

Whatever answer is given to this question, it is certain that the London government will have to negotiate with Brussels about some key aspects of Britain's EU membership. These include its voting power in the Council of Ministers and its representation in the European parliament – both of which will have to be reduced because its population will have decreased. There will also have to be some adjustment to its annual contribution to the EU budget (which should also be reduced).

When all the theatricals surrounding this debate are set aside, the fact remains that it is in everyone interests (Edinburgh, London and the EU) that the Scottish people retain all their rights within the European Union.

The EU is currently waging a desperate struggle in Ukraine and elsewhere with Moscow to demonstrate the superiority of its democratic values. The idea that the Scottish people could be ejected or indefinitely suspended from the EU for opting for national independence is laughable.