BETTER Together, the campaign for a No vote in the independence referendum, will launch tomorrow with a stark warning that there would be "absolutely no going back" if Scotland left the United Kingdom.

In full-page adverts in nine Scottish newspapers, Better Together will proclaim the UK offers the "best of both worlds" – a distinctive Scottish Parliament and the security of a union with Wales, England and Northern Ireland – and argue that Scots don't need to choose between them.

The Better Together logo will be an abstract saltire tilted to show a white-on-blue plus sign to reinforce its claims to be a positive campaign.

However, the text of the adverts will continue to use the familiar pro-Union language of divorce.

Urging Scots to rally behind the UK, the adverts say: "The referendum on independence will be the most important decision of our lifetimes. We must all get involved because the outcome will affect the future of our country and our families. There will be no trial separation. And absolutely no going back."

The media blitz suggests Better Scotland is already well financed, but a spokeswoman for the group last night refused to identify any of its donors.

"We are going to make public our donors from time to time," she said.

However, the Sunday Herald understands much of the start-up money came from Labour and the Conservatives themselves, rather than big-name outside donors.

Yes Scotland has £2 million in its coffers courtesy of the SNP, money which originally came from the late poet Edwin Morgan and the Ayrshire Lottery winners, Colin and Christine Weir.

In contrast to the actors, singers and SNP evangelism of the Yes Scotland launch, Better Together's advent is intended to be low-key, sober affair to underscore its "safety first" message.

Although the Scottish leaders of Labour, the Liberal Democrats and the Tories will be present, the campaign is being spearheaded by Labour, as its voters will be key in deciding the outcome of the 2014 referendum.

Former Labour chancellor Alistair Darling will lead the launch at Napier University.

Darling has attacked the SNP plan for an independent Scotland to keep the pound in a "sterlingzone" with the rest of the UK. He said the "lunacy" of the policy had been exposed by the eurozone crisis, where the key lesson was that a monetary union of the kind proposed by the SNP needed political union too.

Darling said: "To make a common currency work, you would have to have all sorts of eurozone-style rules requiring your budget to be approved by the other country, and you end up, as you have seen in Europe, with a common currency that takes you all the way round to economic and then political union.

"In other words, you go through all the trauma of breaking up the United Kingdom to end up back with it, which is absolutely barmy."

The SNP says there would need to be a "fiscal pact" between Scotland and the Bank of England to make a sterlingzone work, and for the Bank to act as lender of last resort, but denies this makes a divergent Scottish fiscal policy impossible.

Better Together has also hired Blue State Digital, the company which worked on the online campaigns of US President Barack Obama and French President François Hollande, to build its website.

The UK political director of Blue State Digital is Gregor Poynton, a former organiser of Scottish Labour in the two years leading up to the party's defeat by the SNP in 2007.

A Better Together campaign spokesperson said: "The cross-party campaign believes Scotland's interests are best served by staying within the UK."