The Deputy Leader of Scottish Labour accused the SNP of not being progressive and not knowing what they’d do with any powers gained from independence.
Speaking at Scottish Fabians event at Labour party conference urged her Westminster colleagues to reject any notion of working with Nicola Sturgeon’s party.
She said: “No matter how tempting it may be for UK party colleagues to consider a so-called progressive alliance with the SNP, it would be an unmitigated disaster.
"Not just for the Labour party, but also for Scotland.
“Firstly the SNP are not progressive at all, and I challenge you to look at their domestic record and think any different. Secondly, this isn’t going to play well in Scotland.
“It would give truth to the lie that a vote for the SNP somehow has no consequences and somehow you’ll get a Labour government.
"There are consequences.
“SNP insticts are always always anti-Labour.
“They want to steal our clothing to pursue the sole object they have of independence from the rest of the United Kingdom.”
The Dumbarton MSP also claimed SNP voters had to be the target at the next election.
She explained: “English voters do not want to see a nationalist tail wagging a UK Labour dog.
"Who can forget the image of Ed Miliband in the pocket of Alex Salmond?
"It doesn’t matter if that image is true, that image dominated the election and I think it caused us to lose the election, certainly in Scotland.
“People vote for the SNP because they think they're competent and they have a vision but they don't agree with them constitutionally.
“That needs to be our target voter form because the SNP are displaying that they're not competent, that actually their vision amounts to an independence referendum, but no idea of what they would do with the powers when they've got in.
“Middle Scotland, as they’ve been named, that needs to be our target voter pool, and with Anas as leader, and Keir as leader, and a Labour party focused as much on Scotland as it is the UK, I am optimistic about the future.”
The SNP have been approached for comment.