When politicians call one another comrade you can be sure they're fingering a stiletto.

The word should light up police switchboards. It always means someone's in for a carving.

For instance, after Alex Salmond introduced it at FMQs today he went at it like Sweeney Todd.

His victim was Johann Lamont, who had come lightly armed with an audit report on education.

It led to a draining round of attainment tennis.

The FM said it had gone up under the SNP. Ms Lamont said it was declining relative to other countries and the rest of the UK.

The FM said it was better than under Labour. Ms Lamont blamed the Nats... you get the idea.

Only after most folk lost the will to live did the Labour leader reveal she'd been quoting from a draft auditors' report, and that the bad stuff had mysteriously failed to make the final cut.

Had the government suppressed it? she asked. "Is it not the case that the first casualty of this government is truth and the FM does not trust the people of Scotland with the truth?"

The FM deployed Flannel 101: misunderstand the question to avoid answering it.

Ms Lamont was "trying to impugn the integrity" of the auditors, he claimed lamely.

But success was round the corner, as he lobbed in the random fact Ms Lamont had recently described the Tories as Unionist colleagues.

"Next thing you know she'll be calling them comrades in the Conservative Party," he hooted.

Ms Lamont looked like she wanted to plant a hammer and sickle in him. The SNP laughter went on longer than the Volga.

It was also the perfect cue for Ruth Davidson, who was sporting a jacket of deepest red. "Comrade! Comrade!" chanted the SNP backbenches.

The presiding officer cawed in disapproval. "I think the comrade's outfit just sums up the question," the FM laughed.

"I take compliments wherever they're proffered," said the Tory leader, "I don't get many, but I'll take them when I get them."

But Ms Davidson had also come tooled up. As she charted the government's wayward to-ings and fro-ings over the set-up costs of independence, it was the FM who looked pained.

A newspaper report today claimed ministers were only now working up an estimate, and that officials had met top LSE arithmetic boffin Professor Patrick Dunleavy to discuss numbers.

"First Minister, the people of Scotland have to know, what is going on?"

Mr Salmond chortled a little too hard, a sure sign he's squirming like a bucket of bait. More evidence: he then tried to trash the paper's report by revealing it lacked a key fact - that he too met Prof Dunleavy last week.

Jaws in the press box flapped open. This was rather like whining one's way out of a parking ticket by saying it was nothing compared to that 'orrible murder what I done.

It only raised more questions about why the FM was so keen to meet an expert on set-up costs.

LibDem punchbag Willie Rennie was indignant. "This goes from bad to worse, I have to say," he tutted as he took another tilt on costs.

"Willie Rennie should not get to his feet with 'This goes from bad to worse' as his first words," replied Mr Salmond, blade aloft. "That is no way to announce a question at First Minister's questions."

Punctured, Mr Rennie beat a deflated retreat.

But the most cutting remark of all came from Tory Gavin Brown as the FM toiled with a question about his revived plan for local income tax, a wheeze that stank itself into oblivion the last time he tried to make it work.

"Will the First Minister promise to keep the local income tax rate a secret until after the referendum?" asked Mr Brown tongue-in-cheek.

The FM's piercing scowl suggested Mr Brown ought to get himself a stabvest, sharpish.