Scottish nationalists are making a spectacle of themselves by promoting an £11 billion EU export market while rejecting a UK single market more than four times the size, according to Scottish Secretary David Mundell.
Scotland's only Conservative MP has welcomed nationalist parties' support for Europe, but said it is "an odd situation for pro-independence campaigners to want to pull out of the UK but to want to remain in the EU".
In a speech at the Centre for European Reform, Mr Mundell will highlight "the social and economic advantages of the membership of the EU".
He is expected to say: "If Scotland had voted to leave the United Kingdom, those who supported that outcome would have argued that we had achieved 'freedom' from the UK.
"But it would have been a false freedom, which would have restricted the life chances and opportunities available to people in Scotland. The same can be said of the choice we face in June.
"It is an odd situation for pro-independence campaigners to want to pull out of the UK but to want to remain in the EU.
"And it is an even more striking spectacle to see the champions of Scottish independence become advocates of the UK being better together, pooling and sharing as a part of the EU.
"They, rightly, talk up the importance of Scotland's £11.6 billion EU export market, yet they argue that Scotland should leave the UK, a true single market which accounts for £48.5 billion worth of trade for Scotland."
He dismissed Leave campaigners' attempts to link warnings about the risks of leaving the EU to the Project Fear tag applied to unionists in the independence referendum, insisting many unionist warnings have proven well-founded.
"The Yes side dismissed all of the legitimate questions which the No side raised as scare tactics," he said.
"Let's take just one example - the oil revenues an independent Scotland would rely on.
"When No campaigners pointed out that their estimates of oil revenue were too optimistic, and that they were taking a risk with Scotland's economy by relying on such a volatile commodity, we were dismissed. We've seen in the months since how right we were to raise those questions."
He added: "The lesson to be learned from the independence referendum is that when people argue passionately for a major change, but play down the risks, be very wary.
"Pointing out the dangers and asking the difficult questions is not a case of Project Fear but Project Fact.
"We were right to caution about the dangers of Scotland leaving the UK - people had a right to know the risks. And the same applies to the European question."