Brexit supporters and Scottish independence advocates believe in a 'false freedom', says David Mundell

In a speech at the Centre for European Reform in London, he will also question how supporters of Scottish independence can be comfortable campaigning for Britain to stay in Europe, suggesting that both the Union and the EU carry similar benefits such as trade and security.

“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,” he will say. “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.”

He will add: “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.”

Mr Mundell will also suggest that turnout at the June referendum is unlikely to be as high as the 85 per cent achieved at the Scottish independence poll, calling on supporters of Britain remaining in the EU to stress the importance of voting on the doorsteps.

“The danger is that because people don’t feel that their very identity is on the ballot paper, with a box next to it, waiting for them to support it, they may not feel compelled to go out and vote,” he will say. “That’s why a big task facing all of us who think the UK is better off in Europe is in making people understand both the risks we are running with this vote, and the benefits we enjoy as a consequence of our membership of the EU.”