Alex Salmond claimed his party is gaining unprecedented support

He told the SNP spring conference that Scotland was being held back by an executive with too little ambition and a parliament with too little power.

Mr Salmond's claim is based on the party's private polling which suggested the SNP was ahead in all but two regions of Scotland.

The survey also claimed the party was ahead in all socio-economic classes.

Support for independence

Mr Salmond again dismissed Prime Minister Tony Blair's warning that the SNP would cost every Scottish household �5,000 a year.

He said Scots were more likely to believe Sir George Mathewson, the former Chairman of the Royal Bank of Scotland, who revealed his support for independence on Friday.

The SNP leader launched a sharp attack on Mr Blair for his "petulant" attack Sir George.

He said: "A confident prime minister doesn't launch a daft attack on arguably the most successful Scottish businessman of his generation."

Mr Salmond said his party was on the "crest of a wave".

He cited an ICM poll which put the SNP in the lead in all socio-economic groups, a "historic" achievement for the party.

"For a national party, it is extraordinarily important to have that wide canvas across the socio-economic spectrum," he said.

An SNP government will take the decision on independence out of the grip of politicians and put it firmly where it belongs - in the hands of the Scottish people Nicola Sturgeon

The party's deputy leader Nicola Sturgeon told the conference a Nationalist administration at Holyrood would stage an independence referendum in its first term.

And in a clear warning to potential coalition partners like the Liberal Democrats she said this was non-negotiable.

'Negative campaigning'

"An SNP government, in our four-year term of office, will take the decision on independence out of the grip of politicians and put it firmly where it belongs - in the hands of the Scottish people," she said.

"And we will bow to no party that seeks to deny the people of Scotland that right to choose their own future."

Ms Sturgeon went on to accuse Labour of sinking deeper into a "mire" of negative campaigning.

She reaffirmed policy commitments and announced new ones, such as restoring ring-fenced funding of �10m for drugs education in schools.

The deputy leader also said an SNP administration would pioneer a "carbon offset" scheme.