THE UK Government might seek to block any second Scottish independence referendum taking place until after the UK leaves the European Union in 2019, Whitehall sources have suggested.

They have said that it would be “a nightmare” for Theresa May and her ministers to have to negotiate the multiple complexities of Brexit with Brussels and simultaneously fight another Scottish campaign and, if there were a Yes vote, then conduct a whole raft of complicated negotiations with Edinburgh.

“She couldn’t possibly ride two horses. It would be difficult dealing with one set of talks; to have to do another would be a nightmare,” explained one UK Government insider.

He also pointed out that Brussels could seek to exploit any perceived weakness in London’s approach to the Brexit talks on the back of a second independence campaign and, even more so, if there were a Yes vote and talks on the break-up of Britain had to take place at the same time.

On Friday, Manfred Weber, the German MEP who leads the European People’s Party, highlighted the prospect of increased political strife in the UK, noting: “I met the Prime Minister of Scotland and the message was very clear: you have a lot of internal battles to fight and people all over Europe see this."

While the Prime Minister and her ministers have given mixed signals on whether or not they would be willing to facilitate a second independence poll, it is believed, politically, it would be nigh impossible for Mrs May to reject a demand for one from Ms Sturgeon. The FM has already insisted it would be “inconceivable” for her to do so.

But a senior Whitehall source explained how consideration was now being given to granting approval “in principle” for a so-called Section 30 Order, the parliamentary device to grant Holyrood power to hold a referendum, while introducing a sunrise clause, which would prevent the SNP Government from holding it until after the Brexit deal was done.

In 2012, when a parliamentary order to hold the 2014 independence referendum was granted, it contained a sunset clause, stipulating that the poll had to take place by a certain date.

While the publication of the Scottish Government’s own referendum bill makes a poll feasible only as early as spring 2018, any move by Whitehall to restrict the timeframe for Ms Sturgeon to hold so-called indyref2 would cause an almighty political backlash.

The SNP at Holyrood, where there would have to be approval for any parliamentary order, would reject out of hand any move that sought to bind the hands of the Scottish Government; there would also be uproar from their Nationalist colleagues at Westminster.

In parallel, other parties at Westminster, which would also have to approve the order, would object for different reasons; Labour and the Liberal Democrats, not to mention many English Tories, would oppose any move to hold a second independence poll at all.

Getting a new order through Westminster could prove difficult given Mrs May only has a working majority in the Commons of 16 and in the Lords does not have one at all.

One Liberal Democrat peer stressed how his party in principle opposed a second independence poll in this parliament and any idea of the UK Government giving a “flashing amber light” to one in the wording of the parliamentary order would be strongly opposed.

Commenting on the idea of a sunrise clause, the peer added: “If you have another referendum after the Brexit talks, it could be an even worse timeframe because of all the things that have to happen. It would be just chaos.”