David Cameron pledged the Conservatives would "fight with everything we've got" to keep the United Kingdom together as he told Scotland's First Minister to "stop dithering and start delivering" on the independence referendum.
The Prime Minister claimed the union between the countries had made Britain "one of the world's greatest economic and political success stories".
He claimed it was Alex Salmond - who wants to hold the independence referendum in autumn 2014 - who was a "big road block" to a vote on the country's constitutional future.
The Prime Minister used his speech to the Scottish Conservative conference in Troon, Ayrshire, to launch a passionate defence of the Union.
But he also used his speech to tell his party that as well as needing to fight for the future of the country, it must also fight to reconnect with Scottish voters.
On the subject of the referendum, he was clear that Scots should get a "clear choice" in the ballot: "Yes or No, in or out of the United Kingdom".
The Prime Minister said: "Delay creates uncertainty for businesses, investors, families.
"People need to know one way or the other.
"So my message to the First Minister is this: stop dithering and start delivering.
"Let's give the Scottish people the chance to make a clear choice about their future."
Mr Cameron insisted he was eager for the country to "hold the debate, put the question, make the decision".
He conceded the Tories - who have just one MP in Scotland - were "nowhere near" where they should be north of the border.
But he insisted this was not a "fact of life", as he urged party members to "reach out and send out a rallying cry across Scotland".
He told them: "Enough of the hand-wringing and trying to be all things to all people. Let's be clear about what we stand for - and what we won't put up with."
With the debate over Scotland's future taking centre stage, Mr Cameron used much of his speech to defend the Union, which he said was a "partnership for liberty, security, prosperity".
Mr Cameron said: "Scotland is better off in Britain."
He hit out at Mr Salmond and his Scottish National Party administration's plans for a referendum, claiming that by not wanting to hold the poll for two and a half years they were less Braveheart and more like Chicken Run.
The Scottish Government has said it is open to including a third option of enhanced powers for Holyrood on the ballot paper.
But the Tory leader said: "First he wanted a referendum in 2010 - now they say they need 1,000 days.
"First he said they wanted one question - now he's flirting with two. He's talking about devo-max, or devo-plus. Soon it will be devo - the sequel.
"I thought we were going to be watching the movie Braveheart, it turns out it's Chicken Run."
The PM also criticised Joan McAlpine, a Nationalist backbencher at Holyrood who had compared the Union to an abusive relationship.
"What planet are these people on?" he asked.
Mr Cameron went on: "Was it an abusive relationship that stood alone against Nazi Germany? Or that abolished slavery?
"Or that turned these islands into one of the world's greatest economic and political success stories?"
He insisted: "It's not an abusive relationship, it's a Union."
He said it had "shone as a beacon of openness and tolerance the world over for generations".
Mr Cameron went on: "It's not just a place on the map but an idea and an ideal. And it's not just about our history, it's about our future."
The Prime Minister insisted his party had delivered on devolution, with the Scottish and UK governments agreeing earlier this week that the Scotland Bill - which hands Holyrood new powers, including some tax-raising powers - should proceed.
That legislation, he told the conference, would provide a "huge transfer of fiscal powers" along with new borrowing powers.
He said: "This is a Bill delivered in Westminster by a Conservative Prime Minister, supported by the Scottish Government, consented by the Scottish Parliament.
"I promised respect and that's exactly what we're giving."
He also told the conference he was "open-minded about the transfer of more powers" to Scotland "as long as those powers are truly about improving the lives of people in Scotland, not just bargaining chips in some endless game of constitutional poker".
But he said these issues were "principally questions for after the referendum".
As well as fighting to keep Scotland in the UK, Mr Cameron said the party needs to show "that same fight" on all other issues to try to win over Scottish voters.
The Conservatives have struggled north of the border in recent years, losing seats at last year's Holyrood elections.
But he said the election of new Scottish party leader Ruth Davidson "gives us the chance of a fresh start".
He told the conference: "This could be our moment, if we are bold enough, to come back stronger."
He said his party's challenge was to reach out to voters and "reconnect their beliefs with our beliefs".
To do that, he said, delegates must "drive home" that the Tories are a "distinctively Scottish party" and are "passionately patriotic".
He added: "Most crucially, we must show how our values chime with the values of people all over Scotland.
"We've got to show that a love of Scotland does not belong to one party.
"For too long we've let the SNP claim ownership of patriotism. The Saltire is the flag of one nation - not the symbol of a political party."
But he insisted: "I see no reason, no reason at all, why a party that is moderate, sensible, centre-right, cannot represent millions of people in Scotland."
The Conservative leader went on to argue that his party's values chimed with traditional Scottish values.
"This is a nation founded on the virtues of thrift and graft," he said. "Of paying your way, not running up debts.
"There's that profound belief in personal responsibility that gets Scottish workers through the snow to work on a winter's morning.
"There's a take-on-the-world buccaneering spirit, and a passionate belief in family, community, country.
"For Conservatives, looking at these qualities is like looking in the mirror."
While he admitted that was "not how many Scots think of this party" at the moment, he said the Tories must make their case north of the border.
He told them: "It's time we stood up even more strongly for those values we believe in. Because, you know what, when you make a strong argument, people will listen."
SNP MSP Chic Brodie hit back at the Prime Minister, saying all he had to offer Scots was a "vague promise of 'something else' if people vote 'No' to independence".
He insisted: "Scotland is firmly on the road to independence. And if this is the best that the Prime Minister has to offer in his fight to save the union, it begs the question - with friends like these, who needs enemies?"
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