By Graham Fahy Follow@grahamjfahy
David Cameron began his fight for the preservation of the United Kingdom in Edinburgh today.
The prime minister robustly set out the case against independence in his first trip north of the border for two years.
"The fight is now underway for something really precious: the future of our United Kingdom," Mr Cameron said.
"I am 100% clear that I will fight with everything I have to keep our United Kingdom together. To me, this is not some issue of policy or strategy or calculation – it matters head, heart and soul. Our shared home is under threat and everyone who cares about it needs to speak out.
"Of course, there are arguments that can be made about the volatility of dependence on oil, or the problems of debt and a big banking system. But that's not the point. The best case for the United Kingdom is entirely positive. We are better off together."
Mr Cameron insisted that together the countries are stronger and safer because of the influence brought by Britain's permanent seat on the United Nations security council and the reach of the UK's armed forces and anti-terrorist and security capabilities.
The prime minister also underlined the economic benefits of maintaining the union.
"We're richer, because inside the United Kingdom Scotland's five million people are part of an economy of 60 million, the seventh-richest economy on the planet and one of the world’s biggest trading powers", he added.
"Today, Scotland has a currency which takes into account the needs of Scottish economy as well as the rest of the United Kingdom when setting interest rates and it can borrow at rates that are among the lowest in Europe."
The prime minister then met with the Scottish first minister Alex Salmond to address outstanding areas of disagreement with the SNP including the vote's timing, the number of referendum questions and the wording of those questions.
"We had a good and constructive meeting and we discussed issues that really matter to people in Scotland like the state of the economy and the need to get people back to jobs" he said afterwards.
"On the issue of independence, separation, Scotland leaving the United Kingdom, I'm afraid there wasn't much progress.
"I believe that we need to put a straightforward and simple and fair and legal question to the Scottish people in good time, which is to ask the straightforward question: 'Do you want to stay in the United Kingdom' - and I hope that's what people will vote for - 'or do you want to leave the United Kingdom?' I think we need to get on with that … and on those issues I'm afraid we haven't made much progress, which is frustrating".
Mr Cameron refused to be drawn on what further powers would offer Scotland if they vote no. "What I'm offering is that if the answer to the question is that Scotland wants to stay in the United Kingdom, then further options for devolution are on the table, that we can discuss those, just as we have in the past."
The principle differences are whether 'devo-max' should be offered to voters as an option and an SNP proposal to enfranchise 16- and 17-year-olds for the referendum.
'Modest progress' in referendum talks
The Westminster government wants the vote to be held "sooner rather than later", Scottish secretary Mr Moore said on Monday after talks with Mr Salmond. The SNP prefers to delay the vote to build support for a breakaway from the UK.
"I think when you consider that, under their timetable, we've got the best part of three years before we make this momentous decision, I think people across Scotland believe that actually the sooner we can do that, the better," Mr Moore said.
Mr Salmond emphasised the importance of listening to the views of the Scottish people.
"It's right and proper in how you formulate the question that you listen to the views expressed - we've already had thousands of responses," he said.
"I think there's an appetite for people to have their say in deciding Scotland's future."
Both sides appear to be committed to resolving their differences rather than going ahead with a constitutional clash in the courts over the Scottish government's power to hold a referendum on its own terms.
Polls suggest that between 32% and 38% of Scots favour independence and almost 70% favour a form of partial independence known as 'devo-max'.
Undersea cable to help England keep its lights on
Meanwhile, a billion pound contract to lay a power cable under the sea from Ayreshire in Scotland to Liverpool was announced earlier today.
Scottish Power and National Grid have contracted Siemens and cable-maker Prysmian to lay the 420km line which be the longest such underwater connector in the world. The high voltage line is due to be operational in 2016.
Work began on the project in 2009 and the line is intended to open up the potential for Scottish renewable energy by linking to consumers in England.
"This link will have a vital role of play in meeting both the country's energy needs and helping to address the problem of climate change" said national grid director Nick Winser.
"We are investing in an innovative solution, using the most advanced technology.
"As a result, the benefits for consumers and electricity generators in being able to transport power in the most efficient way will be felt for years to come."
Mr Salmond pledged last year that 100 per cent of Scotland's gross electricity consumption will come from renewable sources by 2020, supplied mainly by thousands of wind turbines. He has also claimed the windmills will produce so much power that they will "help to keep England’s lights on".