Prime Minister David Cameron will focus on his fight to keep Scotland in the UK as he opens the Scottish Conservative party conference.

He is due in Edinburgh later today, where he will draw on recent interventions from major businesses, such as BP and Shell, in the referendum debate.

Mr Cameron will attempt to tackle accusations of "scaremongering" over the country's future, saying he wants to "take that myth apart".

Steven Camley's cartoon 

He is expected to say: "This referendum is a major life decision - and you don't make one of those without getting all the information you can.

"You wouldn't buy a house without getting a survey done, you wouldn't choose a car without an MoT, and you shouldn't make a decision about changing your nation - forever - without knowing in full what the consequences may be.

"And look at who's laying out those consequences: the governor of the Bank of England, the president of the European Commission, business chiefs from companies like BP and Shell; Alliance Trust and RBS; Lloyds, Barclays - the list goes on.

"These are not political puppets, they are serious, non-partisan figures. So, the idea that these are empty warnings and political scaremongering is a myth, and we owe it to the people of Scotland to take that myth apart."

Mr Cameron is appearing at the three-day conference at the Edinburgh International Conference Centre just under six months before people in Scotland vote in the independence referendum.

He is expected to repeat his emotional plea to Scots to vote No on September 18 by referring to the upcoming Commonwealth Games in Glasgow.

"When the call went out for volunteers at Glasgow 2014, more than a quarter of those who responded were from elsewhere in the UK," he will say.

"People who were happy to travel hundreds of miles, to stay with friends or relatives, to give their time for free and be part of it.

"Because it's not 'over the border', it's not a foreign country, this is our home, and when any corner of these islands needs back up or support, the rest is there."

Scottish party leader Ruth Davidson said it is fitting that the conference is being held in the country's capital city.

"Let's not be in any doubt about our main priority for the coming months," she wrote in a foreword to the conference agenda.

"There is one issue that overshadows everything else that we do in 2014. The next six months will see us in the fight of our political lives. The very existence of our country is under threat."

The conference opens one day after the most recent opinion poll put support for independence at its highest level for more than six months. The Survation poll suggests 39.3% will vote for independence, compared with 47.6% who said they want Scotland to remain part of the UK.

Deputy First Minister Nicola Sturgeon said the Conservatives have "no mandate" in Scotland.

She said: "As the Tories gather in Edinburgh this weekend, they should not be allowed to forget that it is their austerity agenda that is pushing up to 100,000 more children in Scotland into poverty by 2020. David Cameron's increasingly ham-fisted attempts to scare the people of Scotland into voting No will fool no one.

"Only a Yes vote in September will put an end to the democratic deficit we face under Westminster rule. And only independence can ensure that Scotland gets the government it votes for - every time.

"With recent polls showing support for Yes at its highest since last summer, more and more people are realising that Scotland's future is an independent one."