British Prime Minister David Cameron says he'd be "heartbroken" if Scotland voted to separate from the United Kingdom in an upcoming referendum, calling on independence-minded Scots to look at the future consequences of separation.

"I would be heartbroken ... if this family of nations is torn apart," Cameron told an invited audience at the Edinburgh headquarters of the Scottish Widows insurance firm.

Cameron said he had often been asked if his Conservative Party would stand a better chance in elections without Scotland, which, according to the BBC, currently has only one Tory MP.

"My answer to that is, I care far more about my country than I do about my party," Cameron said. "I care hugely about this extraordinary country, this United Kingdom that we've built together.

"If we pull together, we can keep on building a better future for our children. We can make sure our destiny matches our history, because there really will be no second chances. If the U.K. breaks apart, it breaks apart forever," the prime minister said.

The Associated Press writes:

"Cameron's personal plea aimed to keep the 307-year-old union between England and Scotland intact and prevent himself from going down in history as the U.K. prime minister who lost Scotland. He is likely to face calls from his Conservative Party to step down if Scots vote to secede."In a rare display of cross-party unanimity, Cameron, Labour leader Ed Miliband and Liberal Democrat chief Nick Clegg all pulled out of a weekly House of Commons question session in London to make a late campaign dash to Scotland as polls suggest the two sides are neck-and-neck ahead of the Sept. 18 independence referendum."Copyright 2016 NPR. To see more, visit