Scotland's First Minister Nicola Sturgeon Jeff J Mitchell / Getty Spain would block any attempt by Scottish First Minister Nicola Sturgeon to keep her country in the European Single Market if the rest of the UK leaves, according to a leading Spanish MEP.

Esteban Gonzalez Pons leads the Spanish delegation of MEPs in the European Parliament's largest political grouping, the European People's Party. He told the Telegraph that Sturgeon's single market demands were "impossible."

Scotland voted to remain in the EU by a margin of 62% to 38%. Sturgeon, who leads the ruling Scottish National Party (SNP), believes this gives her the mandate to push for a 'soft' Brexit and keep the country in the single market, a free-trade agreement between countries within the European bloc.

But Pons said that cutting a special deal for Scotland, where Sturgeon is also pushing for a second referendum on independence, could encourage the growing separatist movements in areas of Spain like Catalonia and the Basque country.

He said that the Spanish government will therefore be the UK's "best friend" during Brexit negotiations, and said it shares "the same point of view about the Scottish question" as Downing Street — where Prime Minister Theresa May has comprehensively ruled out any special deal for Scotland.

Pons said: "It’s impossible. Scotland, while it is part of the United Kingdom, has to be the same as the UK. If Spain agrees a special deal for Scotland after Brexit, Spain has to negotiate a special position for Gibraltar [a British territory which borders Spain] and we accept that Gibraltar could be part of the single market."

"We’re not going to accept Scotland in the single market without the rest of the UK," he added.

While the MEP was not speaking on behalf of the Spanish government, he gave the interview after having spoken to Spain's foreign affairs minister, and said his comments echoed the view of the ruling People's Party.

Academics have also warned Sturgeon that striking a separate deal for Scotland is not realistic. Professor Michael Keating, politics professor at the University of Aberdeen, warned in September that such a move would create a "hard border" between Scotland and England, a major economic barrier to free goods and movement.

Scottish Conservative leader Ruth Davidson said: "People deserve the reality, not nationalist spin: and the fact is that European nations like Spain are making it clear that they cannot entertain the SNP's proposals. As Mr Pons says, they are 'impossible'."

A spokesman for the Scottish government said: "Brexit is by far the biggest threat to Scotland’s jobs, prosperity and economy, and that is why we have always been clear that remaining in Europe – and as members of the world’s largest single market – is the best option for our future.

"The people of Scotland voted overwhelmingly to remain in the EU – and we are exploring all options to protect Scotland’s national interests," he said.

He added: "We will set out proposals in the next few weeks that will keep Scotland in the single market even if the rest of the UK leaves."