Labour MEP warns UK could cease to exist after Brexit
Scotland's longest serving MEP has predicted the UK will no longer exist unless a "flexible and imaginative" Brexit solution is found for Scotland.
Labour MEP David Martin was speaking as the European Parliament debated its negotiating objectives after the triggering of Article 50.
MEPs will have to approve any deals between the UK and the EU.
The UK government has previously said a separate Brexit deal for Scotland would be unrealistic.
Instead, it pledged to negotiate a deal that worked for all parts of the UK and called on the Scottish government to focus on that goal rather than a second independence referendum.
The Scottish government published proposals in December which it said would allow Scotland to remain in the European single market even if the rest of the UK leaves, as the prime minister has indicated it will.
The document said this could be done by allowing Scotland to remain within the European Economic Area (EEA).
It argued that the arrangement could safeguard both Scotland's access to the European single market without disrupting free trade across the UK.
Analysis by Nick Eardley, BBC Scotland political correspondent
Labour as a party has been trying to cement its unionist credentials in recent weeks - offering more devolution as part of a federal model, but saying it will resolutely oppose independence.
But David Martin shows the dilemma some face - ideally they'd like to remain in the UK and the EU. But that's not an option - so which would they prefer?
Mr Martin is Scotland's longest serving MEP and he believes in the European project. And that, as he told us last month in Brussels, means he's not sure how to vote if there's another independence referendum.
And he thinks others feel the same, meaning the union is hanging by a thread. He says if the UK doesn't show flexibility in dealing with the Scottish dimension - it soon won't exist.
In that sense, his comments echo much of what SNP politicians have said on the subject. That explains why the SNP's deputy leader Angus Robertson tweeted his support.
Mr Martin told MEPs during the debate in Strasbourg that the feeling in Scotland was that "we are being dragged out of Europe against our will - a feeling only compounded by Mrs May's determination to pursue a hard Brexit".
He added that the Scottish government's proposals were an "imaginative and flexible solution for Scotland" which "deserves serious consideration in this house".
The Labour politician went on to warn: "If the UK is not flexible in these talks, the UK will not only be leaving the European Union. The UK will cease to exist."
The UK government has said it is looking carefully at the Scottish government proposals - but has not yet given any indication it is likely to pursue them during the forthcoming negotiations with the EU.
Speaking in the House of Commons last month, Prime Minister Theresa May insisted Scotland would be leaving the EU regardless of whether or not it was independent.
She added: "What we need now is to unite, to come together as a country and to ensure that we can get the best deal for the whole of the United Kingdom."
Mr Martin, who has been an MEP since 1984 and voted against independence two years ago, has previously revealed that Brexit had left him unsure how he would vote in any future independence referendum.
'Lot of questions'
Interviewed by the BBC's Good Morning Scotland programme ahead of the debate, he again insisted he had "no idea at the moment" about where he stood on independence.
He added: "The very fact that I can't give you a straight answer indicates that I have moved. If you had asked me that question 18 months ago it would be a definitive that I would vote to remain in the United Kingdom.
"Now I think Brexit has put up a whole lot of questions that have yet to be answered."
His stance potentially puts him at odds with Scottish Labour leader Kezia Dugdale, who has insisted that the party would never support independence while she is leader.
A spokesman for Scottish Labour distanced the party from Mr Martin's comments, saying: "Leaving the UK would mean an extra £15bn worth of spending to cuts to schools and hospitals in Scotland.
"Labour will never sign up to something that would be so catastrophic for working families in Scotland."
But the Scottish Conservatives said the MEP's remarks suggested that Labour was "all over the place" on the constitution, and that the Tories "are the only party serious about keeping Britain together".
Speaking to reporters during a visit to Edinburgh in December, UK Chancellor Philip Hammond appeared to rule out a special Brexit deal for Scotland, saying it was "not realistic".
He added that it was "clear that we can't have a different deal or different outcomes for different parts of the UK", and that it would be a "disadvantage" for Scotland to be outside whatever new relationship the UK negotiated with the EU.
This echoed earlier comments from Scottish Secretary David Mundell, who told MSPs that while Scotland's concerns would be "right at the heart of the process", there would be no "special deal".