Image caption Mr Leonard said he had opposed PFI when it was introduced by a Labour-led administration at Holyrood

There are few things more damaging to political equanimity than the laughter of opponents.

Indeed, perhaps there are only two. The laughter of colleagues (unless it is friendly and anticipated.) And then there is pity.

Labour's Richard Leonard found himself on the receiving end today. Opponents, mainly on the SNP benches, chortled mercilessly as he began to question the first minister.

And Nicola Sturgeon herself offered apparent sympathy. Faux pity, as she would doubtless say, now that she has taken to lampooning the courageous use of the French language, first essayed by Murdo Fraser of the Tories.

At one point in her response to Mr Leonard, she paused briefly to intone the word "Bless" in his direction. Faux pity en plus.

And the cause of this comedy and compassion? Mr Leonard sought to pin the FM down over the use of private capital in funding public sector projects.

As he depicted the situation, drawing upon an Audit Scotland report, Ms Sturgeon was guilty of wasting public funds on a gargantuan scale. It was, he said, a scandal.

But the laughter, Brian? The pity? Well, you see, critical MSPs in the chamber - brutes that they are - insisted on glancing back at relatively recent history.

They remembered - curse their 2020 hindsight - a previous Scottish administration which had relied substantially upon the Private Finance Initiative, or PFI.

Image caption Ms Sturgeon showed mock pity for Mr Leonard while her SNP colleagues broke down with laughter

A Labour-led administration, as it happens. Which is why Mr Leonard's indignation generated mocking laughter. John Swinney, as is his wont, rocked and roared in his chair

In advance of First Minister's Questions, Team Sturgeon ponder over what might be asked. Education? The NHS? Crime? The constitution? Ferret-taming?

Never, she said, did she imagine that Labour would resort to asking about PFI - or, more precisely, its modern equivalent, NPD (Non Profit Distributing.)

Why? Because the PFI contracts signed by Labour and others had wasted billions. They had generated excess profits for the private sector, without sharing risk equitably.

They had left a legacy cash burden to be paid by contemporary taxpayers. NPD had sought to remedy these problems and, according to the FM, had succeeded in significant measure.

Mr Leonard wasn't finished. As his opponents sat mute and mostly open-mouthed in astonishment, the Scottish Labour leader recalled that, as a trade union official, he had written a paper condemning PFI, some 25 years ago.

This showed, he said, that he had been consistent on the issue.

Image copyright Getty Images Image caption Scottish Conservative leadership candidates Jackson Carlaw and Michelle Ballantyne have traded barbs in the media in recent days

Ms Sturgeon, however, didn't see things quite that way. It showed, she argued, that Mr Leonard's own Labour Party had ignored his entreaties while it had taken an SNP government to act.

The Labour leader will have better days. Indeed, he has had several trenchant outings in recent weeks. This just wasn't one of them.

And the other parties? Jackson Carlaw left off dissing his rival for the Tory leadership to pursue the FM, once again, over her record on education.

In truth, there was little progress here. The two leaders poured statistics on each other, which seemed to increase in complexity exponentially as the exchanges wore on.

One half expected the Presiding Officer to set an exam on the content at the end.

Cautious demeanour

The discourse with Patrick Harvie of the Greens was more measured. As it would be, with the Scottish budget due to be published in a week's time.

Ms Sturgeon may well need the support of Mr Harvie and his verdant chums to get that budget through Parliament. Hence her notably cautious demeanour.

In essence, Mr Harvie suggested that the Scottish government might usefully adopt the entirety of his party's economic programme. (I exaggerate, but only a little.)

He wanted a "climate emergency Budget" - with minimal expenditure on roads and extra cash for public transport, including free buses for young folk.

Ms Sturgeon responded sympathetically - while inserting references for a need to a balanced approach.

And then it was Willie's turn. Willie Rennie, that is. Ms Sturgeon expects no favours from the Liberal Democrats - and thus the exchanges tend to be rather frank.

So it was today. Mr Rennie chided her over failings in the NHS, including missed waiting time targets.

Nicola Sturgeon said that he would have a little more credibility if he owned up to his own party's coalition role in assisting the Tories to instigate austerity.

Mr Rennie responded by suggesting, equally bluntly, that she might stop blaming everyone else but herself.

In the chair, the PO, Ken Macintosh, looked on with genteel dismay. Such behaviour.