David Cameron has insisted he will not resign if Scotland votes Yes tomorrow, saying his future will be decided soon enough at May’s general election.

The Prime Minister was questioned about the political embarrassment the failure of the Better Together campaign would cause during a visit to a factory in Hampshire on Wednesday.

“My name is not on the ballot paper,” he said.

“What's on the ballot paper is 'does Scotland want to stay in the United Kingdom, or does Scotland want to separate itself from the United Kingdom?'.

"That's the only question that will be decided on Thursday night.

“The question about my future will be decided at the British general election coming soon."

In a key speech delivered in Aberdeen on Monday, Mr Cameron acknowledged his unpopularity in Scotland, which has been used repeatedly as a tool by the Yes Scotland campaign.

A graphic made by the Yes Scotland campaign (Yes Scotland)

“If you don’t like me – I won’t be here forever,” he said.

“If you don’t like this Government – it won’t last forever. But if you leave the UK – that will be forever.”

With the opinion polls still on a knife-edge, there is dismay among Tory MPs at the prospect of a possible Yes vote.

Some backbenchers are angry at the way the three main party leaders have promised greater devolution of powers to Scotland while continuing higher levels of public spending and some are calling for the creation of an English Parliament to stop MPs from other nations voting on English issues.

Mr Cameron sought to play down suggestions of unrest within his party, saying all members believed in “our family of nations”.

In pictures: Politicians scramble for Scotland Show all 6 1 /6 In pictures: Politicians scramble for Scotland In pictures: Politicians scramble for Scotland Politicians scramble for Scotland Labour Party leader Ed Miliband speaks during a campaign meeting in Cumbernauld in Glasgow Reuters In pictures: Politicians scramble for Scotland Politicians scramble for Scotland British Prime Minister David Cameron gestures as he speaks during a visit to Scottish Widows offices in Edinburgh Getty Images In pictures: Politicians scramble for Scotland Politicians scramble for Scotland Scotland's First Minister Alex Salmond campaigns for a Yes vote in east Edinburgh, Scotland EPA In pictures: Politicians scramble for Scotland Politicians scramble for Scotland John Prescott campaigns for a 'No' vote in the referendum on Rutherglen main street in Glasgow Getty Images In pictures: Politicians scramble for Scotland Politicians scramble for Scotland Liberal Democrat Deputy Prime Minister Nick Clegg talks to the media during a campaign visit to the market place in Selkirk Getty Images In pictures: Politicians scramble for Scotland Politicians scramble for Scotland Better Together campaign leader Alistair Darling speaks to the public in Glasgow Getty Images

“The Conservative Party and all our backbenchers want to see the United Kingdom survive and thrive,” he said.

Despite admitting he felt “nervous” ahead of the vote, he insisted that he was confident about the case for a No vote.

“Well of course everyone who cares about our United Kingdom - and I care passionately about our United Kingdom - is nervous,” he added.

“But I'm confident that we've set out how Scotland can have the best of both worlds.”