Former Prime Minister Tony Blair may form part of a "call to arms" to keep the UK together and grow its economy, it has been suggested.

Alistair Darling, who held several cabinet posts in the Blair administration before becoming Chancellor of the Exchequer under Gordon Brown, today confirmed that he will play a major part in the No to Independence campaign.

He also welcomed reports that Blair is returning to domestic politics.

"He's got a lot to contribute and I hope he'll contribute more in the future," Darling told the BBC's Andrew Marr Show.

He said: "The context here is that there are a growing number of people who recognise that unless we can get growth going in the economy, then the standards of living of people in this country, and their jobs prospects are going to be so much worse.

"It's interesting. The centre of political gravity is shifting. You can see that the Tories are rattled by this.

"Why else would David Cameron be calling for growth in Europe, something that he has conspicuously failed to do in the two years that he has been Prime Minister.

"So I welcome, you know, this is a call to arms, if you like, whether it's the constitution in Scotland or whether it's the economy in whole United Kingdom, this is the time for people to stand up and be counted."

Darling said he will have no difficulty working with political opponents in the No to Independence campaign.

He said: "I think it would be ridiculous to say, well, I'm not going to cooperate with someone who actually agrees with me.

"You know, you'll see some odd bedfellows on the other side of the argument I suspect."

However, Labour's leader in Scotland Johann Lamont today cast doubt on whether the referendum will be held at all.

"Alex Salmond seems to have learned the wrong lesson from Tony Blair," wrote Ms Lamont in the Scotland on Sunday.

"The lesson from Blair is not that cosying up to Rupert Murdoch is the key to success.

"Rather, it's when you have won a landslide call your referendum quick.

"After the landslide of 1997, Tony Blair called the referendum on devolution within four months. He built on his momentum.

"The fact that even at the height of his popularity Alex Salmond didn't want to call his referendum suggests he believed he would lose. Indeed, he said as much to one of Rupert Murdoch's papers last week.

"We will be ready when - perhaps, if - the referendum comes and will not be complacent."

A Labour spokesman said: "This is a once in a lifetime chance for Alex Salmond, and Johann is making the point that maybe he will chicken out.

"What if it gets to 2014 and Salmond sees the way the polls are going, thinks he can't win and pulls it?"