STRANGE phenomenon, the late Maggie Thatcher, and the way her invocation still has the power to reduce Holyrood to the level of a playground fight.

Yesterday's FMQs was not a high-water mark in parliamentary rhetoric, and Labour's Johann Lamont was twice invited by the Presiding Officer to withdraw remarks which questioned Alex Salmond's honesty.

This, of course, is another of these conventions we have adopted from Westminster, where the Members are honourable and must never be accused of lying, which famously gave rise to such creative constructs as "terminological inexactitude" or "economical with the actualité".

Holyrood was discussing plans for an oil fund - you wait 30 years and two come along at once - and new evidence casting doubt on whether there would be pennies to spare for either of these piggy banks.

Ms Lamont merely described answers from the First Minister as "dishonest" and all hell broke loose, with screams of outrage prompting the PO to invite her to withdraw the remarks, which she didn't, merely offering the alternative wording of "not being accurate", which failed to quiet the baying Nationalist hordes.

She then compounded this with the observation that "honesty is not something his Government deals in", prompting more mock outrage and a further invitation to withdraw from the increasingly sharp-voiced PO. There was a bit of waffle but no actual withdrawal.

We had got to this fever pitch because Ms Lamont had dropped the "T" bomb - reminding the Nationalists that they voted down the Labour Government 34 years ago, ushering in the Thatcher era.

This is the equivalent of handing round crystal meth to her backbenchers, turning them instantly into crazed hyenas, even although this all happened before some of them were born.

Alex Salmond retorted that it had been Labour Party anti-devolutionists who had brought down the Callaghan government "as Johan Lamont should know, she was one". Cue wild SNP cheering, jeering and desk-slapping. My God, these two tribes hate each other.

But then a strange thing happened. Ruth Davidson led the Tories into the same battle over the two papers on the oil fund and said she had fed them into university cheat software, which showed that the most favourable passages survived in both. "This is from the Alistair Campbell school of dodgy dossiers," she said.

The Labour backbenches went wild. A moment before, they had been in anti-Thatcher mode. Now a Tory leader mocking a Labour figure had them in ecstasy. It's a strange game.