The Scottish Labour party launched a series of attacks on the first minister, accusing his party of hypocrisy over taxation policy in a final effort to win back several hundred thousand Labour supporters believed to have switched sides to back independence.
YouGov found on Monday that 30% of Labour voters were likely to vote yes on 18 September, potentially swinging the result in the last weeks of the campaign and forcing Labour into a rearguard action to stem the haemorrhage of votes.
In a bid to exploit divisions between the Scottish National party and its leftwing partners in the yes campaign, the Scottish Green party and the Radical Independence Campaign, Labour challenged all three groups to name a single Scottish government tax policy which transferred wealth to the poor.
With Labour dispatching more party organisers north to help the final stages of the campaign, its Scottish leader, Johann Lamont, visited pro-UK voters in the Glasgow Govan constituency held by the Scottish deputy first minister, Nicola Sturgeon.
Lamont said: "What really matters is that the SNP are asking Labour voters to vote against their own interests." Voters "are being asked to take a punt by voting yes, and everything will be OK".
Sturgeon retorted: "I can understand why Johann Lamont wants to speak to SNP voters in my constituency – after all, there are a lot of them – but having seen the returns we've been getting in the area she represents, perhaps she would be better off paying attention a little closer to home."
Labour says SNP ministers have struggled to find any redistributive policies in their independence white paper, except a 3% cut in corporation taxes which would simply enrich big companies.
Party officials cited House of Commons Library research which found Edinburgh-based finance company Standard Life would earn £24m extra from that cut and the energy firm Scottish Power would pocket £16.6m.
"He's in a joint alliance with the Tory party and of course at Westminster they have pledged to continue Tory austerity policies. And that's why he's got no credibility on these issues," said Salmond.
Opinion polls found that support for independence rose sharply in late August, putting a yes vote only three points away from a majority, after Salmond alleged the NHS in Scotland was under direct threat from a future Tory government.
Labour insisted its case against the SNP was bolstered on Friday after only two of the SNP's six MPs were at Westminster to vote on a rebel Liberal Democrat motion to water down the bedroom tax – a widely disliked policy which has been central to the Yes Scotland campaign against the Westminster government.
Miliband said the defeat of the Tories in the vote underlined his case that Cameron's authority at Westminster was being steadily eroded while the SNP's case was undermined by the Commons vote.
"Alex Salmond tries to con people into thinking he stands up for social justice. What happened today is that the majority of his MPs could not be bothered to turn up to abolish the bedroom tax," Miliband said.
Eilidh Whiteford, one SNP MP who voted in the Commons, said the motion had still failed to abolish the bedroom tax. "Every single Scottish MP could vote against the bedroom tax and we would still be faced with it because we can be outvoted by Tory votes from the south," she said.
Jonathon Shafi, a senior figure in the Radical Independence Campaign, said it was delighted Labour was campaigning on social justice and tax issues.
"Our contention is that the austerity consensus at Westminster is being repudiated by people voting yes, but that a yes vote is just the start. The urgent fight that will face us post-independence is that we don't swap one Westminster establishment for another at Holyrood," he said.
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