After comments made by Mariano Rajoy, Prime Minister of Spain concerning an independent Scotland's membership of the EU, Better Together leader Alistair Darling said:
This is another blow to Alex Salmond's claims that nothing would change if we vote to go it alone. The Spanish Prime Minister has just made it clear that everything would change.
We now know what the position of the Spanish government would be if we vote for independence. This has created even more uncertainty.
The Prime Minister of Spain has said that Scotland will remain outside the European Union if it becomes independent of the UK.
EU rules state that new countries require a unanimous vote by existing member states if they are to join the union.
But speaking today at a joint press conference with France's Francois Hollande, Spanish PM Mariano Rajoy suggested he would use his country's veto if Scotland applied.
"It is very clear to me, as it is for the rest of the world that a region that obtains independence which is part of a nation state of the EU will stay outside the EU," he said.
"The citizens know it, the Scottish know it - as do all the rest of the citizens of the EU."
Spain's position may be influenced by the likelihood of a would-be independent Catalonia also wanting to remain within the union.
The college of arms says if Scotland does become independent, the Cross of St Andrew will remain at the heart of the Union flag, where it has been for hundreds of years.
And whatever the future holds for Scotland, its proud history will be forever entwined with that of the rest of the UK.
ITV News presenter Julie Etchingham has this report: