THE look of relief on Johann Lamont's face at the end of her speech to the Scottish Labour conference yesterday said it all.

It was an event which had been tipped for disaster. Furious at the tax options being studied by her Devolution Commission, MPs were reported to be staging a boycott in one of Labour's traditional cross-border feuds.

But the splits failed to materialise. The Devolution Commission brought forth a compromise on income tax that, while ungainly, received unanimous support from delegates and defused the row.

The party also unveiled a mini-manifesto, Together We Can, with a pledge to restore the 50p income tax rate for high earners.

Things were far from perfect. It emerged on Friday that the Commission had overlooked Labour's other tax plan, for a 10p starter rate, for instance.

But by and large, this weekend in Perth has been decent for Labour.

The party has sharpened its dividing lines with the SNP ahead of the referendum and Holyrood election.

It has started trying to reclaim the "progressive" mantle from Alex Salmond, insisting that, down the decades, Labour has been the true party of social justice and equality.

But while a new plan is coming together, Lamont's speech was a reminder of a persistent problem.

An hour earlier, former First Minister Henry McLeish told his party it needed to "stop hating Salmond and the SNP". Lamont's speech was a prime example of what he meant.

Time and again she contrasted her personal honesty with the "dishonesty" of the SNP. Salmond was running the most "dishonest, deceptive and disgraceful" campaign in Scottish history, she said.

A joke about Salmond only just discovering women give birth, and Lamont being joined on stage by her two teenagers, were read by some as subliminal references to the First Minister not having children.

It was spiteful, reeking of Labour tribalism, and her audience loved it.

It also overwhelmed other points, such as the reminder that social justice is hard-won and cannot be guaranteed by independence.

If Labour keeps up such attacks, its more reasoned arguments will be lost in the noise.