Nicola Sturgeon has dismissed the prospect of an anti-austerity alliance with Jeremy Corbyn, condemning the new Labour leader for being "unable to unite his party on any of the big issues of our day".
Opening the party's autumn conference in Aberdeen, the Scottish First Minister and SNP leader made her most outspoken attack on Mr Corbyn, claiming it was SNP pressure that forced Labour's U-turn on backing George Osborne over his deficit plan.
She also told SNP supporters the party still has to convince voters opposed to Scottish independence before another referendum can be called, saying it would be "wrong" without "strong evidence" that a "significant number" had switched.
Nicola Sturgeon: "Labour is unreliable, unelectable and unable to stand up to the Tories."
Her address to the party's largest ever conference - 5,000 are expected to attend - came the day after Labour eventually agreed to vote against the Chancellor's Fiscal Charter, which would have enshrined in law his deficit plan.
Ms Sturgeon, who hailed the party's membership surging from 85,000 to 114,121 in a year, said there was "much that I hoped the SNP and Jeremy Corbyn could work together on" but it has become "glaringly obvious" his party is divided under him.
In full, she said:
"Labour initially planned to vote for George Osborne's austerity charter. It was only SNP pressure that changed their minds.
"Or, at least, it changed some of their minds. In the vote last night, Labour divisions were laid bare.
"And it became crystal clear, yet again, that the only party with the unity and the conviction to stand strong against austerity is the SNP.
"You know, there is much that I hoped the SNP and Jeremy Corbyn could work together on.
"But over these last few weeks, it has become glaringly obvious that he is unable to unite his party on any of the big issues of our day.
"When he says he opposes Trident, he is attacked, not just by the Tories, but by his own shadow cabinet.
"When he says he opposes the welfare cap, he is opposed, not just by Iain Duncan Smith, but by his own Shadow Justice Secretary."
She added: "Whether on the economy, or Trident, or even the question of whether UK forces should take part in air strikes on Syria, Labour is a party divided and in disarray.
"In fact, the only thing clear about Labour - and it becomes clearer by the day - is this. Labour is unreliable, unelectable and unable to stand up to the Tories."
On a second independence referendum: "To propose another referendum in the next parliament without strong evidence that a significant number of those who voted 'No' have changed their minds would be wrong and we won't do it."
Her remarks on the referendum are designed to draw a line under any speculation over when another vote may take place to take the pressure off SNP MPs and MSPs likely to be pressed on the issue during the three-day event.
Ms Sturgeon is attempting balance the views of impassioned pro-independence campaigners - many who joined the party in droves after the failed vote last year - with the political reality of knowing that it must win if another referendum is secured.
The party is looking to secure its third term at the helm of the Scottish Parliament in Edinburgh at next year's elections, and a time-table of when a referendum could be called is expected to be included in the manifesto.
She told the audience the "principles" behind the manifesto will be "respect and democracy".
"I believe with all my heart that Scotland should be an independent country. But I respect the decision that our country made last year," she said.
"So let me be clear. To propose another referendum in the next parliament without strong evidence that a significant number of those who voted 'No' have changed their minds would be wrong and we won't do it.
"It would not be respecting the decision that people made."
He acknowledged to delegates that there is still a job to "inspire people who voted 'No' last year to vote SNP".
She said: “For those who want Scotland to be independent, there is only one vote next year that makes sense – and that is a vote for the SNP.
“But I don't just want to win the votes of independence supporters. I want to inspire people who voted No last year to vote SNP too."