David Cameron sought to match Gordon Brown in emotion as he urged Scots not to use the independence referendum just to kick the "effing Tories" yesterday.

The Prime Minister said the rest of the UK was so keen for Scotland to remain part of the UK that they were holding their breath for the result of next week's referendum.

The Tory leader appeared close to tears at one stage as he campaigned in Edinburgh at a hastily arranged event, scheduled after a poll at the weekend suggested a lead for the Yes camp for the first time.

But his message contained sticks as well as carrots.

He warned Scots that attempting to use the pound without a formal currency union could mean financial institutions fleeing south of the Border and an independent Scotland "running out of money".

In a comment piece published overnight he had also warned that if Scots choose to leave the UK in next week's vote they cannot later change their minds.

There would be no "second chances", he said.

There had been question marks over whether the visit of an unpopular Conservative leader north of the Border would prove counterproductive.

The decision to place himself as one of the figureheads of the campaign at this late stage also raise the stakes personally for the Prime Minister.

Already there have been reports that many Tory MPs would want him to resign if Scotland backs independence.

Earlier this week former Labour Prime Minister Mr Brown welled up as he attacked the SNP's campaigning on the NHS and recalled how the service had helped his first child, Jennifer, who died at just 10 days old.

In his own passionate appeal, Mr Cameron hit back at those who have suggested he would personally benefit from independence and the resultant loss of dozens of Labour MPs.

He said he cared far more about this country than he did about his party.

And he showed the strength of his feeling with highly unusual language for a Prime Minister, urging those who want to use the vote to kick the "effing Tories" to take a more long-term view.

By the end of a question-and-answer session at the Scottish Widows office in Edinburgh, he was glassy eyed-and there was a catch in his throat.

He pleaded with the hundreds of employees who had come to hear him speak that "coming into the final days... please be in no doubt the rest of the UK is watching and listening, we are holding our breath. We care passionately about this united nation and we really would be desperately sad to see it torn apart."

The carefully controlled session, not open to members of the public, stood in direct contrast to SNP leader's Alex Salmond's walkabout on the streets of the city at the same time.

Some of those listening and asking questions were also clearly less than impressed with the Conservative leader's emotional appeal.

One woman tackled the Prime Minister over his terminology and whether or not his pledge on extra powers could really be called "guaranteed".

Another asked if all MPs would give up their proposed 10 per cent pay rise to show their commitment to Scotland.

She also asked if the ­Conservative leader could give her a timetable for withdrawal of Trident from Scotland - not in the event of a Yes vote, but in the event of Scots voting No.

Last night Mr Salmond accused "Team Westminster" of panicking in the face of potential Scottish independence.