THE threat to the 300-year-old Union comes as much from “English indifference” than Scottish Nationalism, David Lidington, the de facto Deputy Prime Minister, has admitted.

The Cabinet Office Minister acknowledged that a no-deal Brexit would make the break-up of the UK more likely. Asked if the Union could survive Britain crashing out of the EU without an agreement with Brussels, he replied: “The UK would be under much greater strain in the event of a no-deal.”

Interviewed on BBC Radio’s World at One, before Theresa May makes her final speech in Scotland this evening on the Union, Mr Lidington said he believed the UK was now under greater strain than at any point in his lifetime.

He said: “The threat to the Union comes not just from Scottish Nationalism or pressure for Irish unification, it comes from indifference amongst English opinion to the value of the Union. There is a sense in which we take the Union for granted.”

The Buckinghamshire MP added: “Sometimes there are too many people in England, including in my party, who assume that you can be dismissive of the contribution that Scotland or Northern Ireland makes.”

Last month, a YouGov poll of Tory members found that almost two-thirds – 63 per cent - would be willing to allow Scotland to leave the UK to see Brexit realised.

In response, Ruth Davidson, the Scottish Conservative leader, said there were a number of people in her party who needed to “take a long, hard look at themselves”.

When Boris Johnson declared it was “do or die” on Brexit, Ms Davidson responded by telling him it was “the Union do or die".