Media playback is unsupported on your device Media caption Supporters launch the 'Yes' campaign for Scottish independence

The "yes" campaign for independence wants one million Scots to sign a declaration of support by the time of the referendum in the autumn of 2014.

Scotland's First Minister Alex Salmond said independence would happen if that milestone was achieved.

The pledge was made at the launch of the Yes Scotland campaign in Edinburgh.

However, pro-union supporters believe independence remains largely unpopular among the Scottish electorate and will not happen.

The Scottish National Party played a leading role in the campaign, which was launched at Cineworld in Edinburgh and included other parties, celebrities and businesses.

What does the Yes Declaration say? "I believe that it is fundamentally better for us all if decisions about Scotland's future are taken by the people who care most about Scotland, that is, by the people of Scotland. "Being independent means Scotland's future will be in Scotland's hands. "There is no doubt that Scotland has great potential. We are blessed with talent, resources and creativity. We have the opportunity to make our nation a better place to live, for this and future generations. We can build a greener, fairer and more prosperous society that is stronger and more successful than it is today. "I want a Scotland that speaks with her own voice and makes her own unique contribution to the world - a Scotland that stands alongside the other nations on these isles, as an independent nation."

A pro-union campaign is expected to launch later this year.

Mr Salmond said: "We unite behind a declaration of self-evident truth.

"The people who live in Scotland are best placed to make the decisions that affect Scotland.

"We want a Scotland that's greener, that's fairer and more prosperous.

"We realise that the power of an independent Scotland is necessary to achieve these great ends."

Some of the people who pledged their public support for the campaign did so for the first time.

Actor Alan Cumming, who has been based largely in the US, tweeted after the launch that he would "becoming a resident of Scotland again in order to vote in 2014".

Other "yes" backers included:

actor Sir Sean Connery

former BBC Scotland head of news Blair Jenkins

poet Liz Lochead

musician Pat Kane

actor Brian Cox.

Mr Salmond told the gathered media: "I want Scotland to be independent not because I think we are better than any other country, but because I know we're as good as any other country.

It was left to Liz Lochhead, Scotland's Makar, to recall from one of her finest plays that the Scots national pastime is frequently "nostalgia"

"Like these other nations, our future, our resources, our success should be in our own hands."

The campaign will be built "brick by brick" across communities, he said.

Mr Salmond said that the case would be taken to the people by community activism and "online wizardry".

He added: "By the time we enter the referendum campaign in autumn 2014, our intention is to have one million Scots who have signed the independence for Scotland declaration.

"Friends, if we achieve that, then we shall win an independent Scotland."

Mr Salmond was supported at the launch, which was hosted by Greenock actor Martin Compston, by Scottish Green Party co-leader Patrick Harvie.

He told the 500-strong gathering: "Greens are not nationalists. In fact, we are probably more comfortable than most parties in acknowledging the range of views that exist in our membership and our voters about the question of independence.

"But I believe, as most of us do, that the range of powers currently still held at Westminster simply make no sense from a Green perspective.

"I certainly look forward to helping develop a clear and compelling case for Scotland to take a bold and radical step and vote Yes to independence in 2014."

SNP ministers, who want to hold a referendum in autumn 2014, have been holding talks with the UK government over the arrangements.

Yes Scotland, which has also won the support of the Scottish Socialist Party, is being billed as the biggest community based campaign in Scotland's history, designed to build a groundswell of support for an independent Scotland.

Meanwhile, former chancellor Alistair Darling, a Scottish Labour MP, pointed to a poll he had commissioned which suggested that 33% of those surveyed agreed that Scotland should become independent with 57% opposed and 10% undecided. The poll by YouGov took the views of 1,000 voters.

After the Yes Scotland launch, Mr Darling told the BBC: "The real problem that the nationalists have got is that their momentum has stalled and we can see from the poll that only one person in three has actually bought their message.

"I believe that people will come to see that we are better and stronger with the UK."

"I think that there are an awful lot of risks in simply walking away from the UK."

Mr Darling has been involved in meetings with Conservatives and Liberal Democrats to take forward the plans for a pro-union campaign which is expected to launch later this year.