Throughout history, various events have conspired to propel leaders from high office. Lost wars, economic calamity, scandal, those slings and arrows of outrageous fortune.

Humza Yousaf quit as First Minister of Scotland because he was snippy with a couple of folk and they were awfy upset about it.

That, at any rate, was Mr Yousaf’s version of events as set out in his resignation statement in Bute House following a chaotic few days in Holyrood after he made the surprise announcement to end his power-sharing deal with the Scottish Greens.

He said he still believed it was the right decision to end the Bute House Agreement with the Greens; it was how he did so that was the problem. He had “clearly underestimated the level of hurt and upset” caused and for that he had to go.

He is either deluded or daft if he thinks his problems stretch back only as far as a week ago and involve nothing more than adopting the wrong tone. His was a resignation waiting to happen if ever there was one.

So here we were again, back in Bute House. To Mr Yousaf’s left was a portrait of Winnie Ewing. Opposite her was Robert Burns. If paintings could come to life for a second Madame Ecosse and the ploughman poet would surely have shaken their heads at the scene before them. This was Scottish politics reduced to small matters, a spat between neighbours, an error over tone.

At least Mr Yousaf had lasted longer than a lettuce, the current standard by which time in office is measured. At 13 months - unlucky for some - he had given a packet of Rich Tea biscuits a run for its money. Whatever the timespan, his tea was oot.

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He left the room without taking questions, a poor show given that this was the second time in a week the media had raced down to Bute House at his behest. The BBC’s Scotland editor, James Cook, was even wearing white running shoes.

Getting on board with the athletics theme, Mr Yousaf spoke of independence being “frustratingly close”, of how the last few miles of a marathon were the hardest, but now he was handing the baton to a successor who would lead “us” over the finish line.

In reality, Mr Yousaf had run his race with all the poise of a man whose laces had been tied together. Whether he fell over under his own steam or was pushed, hardly seemed to matter much any more. He was always going to take a tumble. As one of his colleagues said, it was a matter of when not if.

That it should end like this will have surprised no one. Mr Yousaf led his party and the country in an underwhelming fashion and he left office the same way.

True, he inherited several in-trays of problems from his predecessor, Nicola Sturgeon. Yet he added to the pile when he became First Minister. Recent events were entirely of his own making. It was his powerplay that backfired. It was his decision to push on with policies that were clearly at odds with public opinion. Time and again, required to rise to a challenge, he fell short. And now, just like his predecessor, he leaves a mess that someone else must clear up.

In the end, he even flunked his departure. It had taken only a few hours for him to wreck his premiership, but he dithered for days about tendering his resignation. Like so much else to do with Mr Yousaf, the abiding impression was of a man making it up as he went along.

As Mr Yousaf said, politics can be a brutal business. The job of First Minister, Prime Minister, or any leadership position, soon finds a person out.

The public will understand his being overcome with emotion as he thanked his family for their support. It is a sad day for him, and for them. But like the now former First Minister, the country needs to move on. The chaos of the past week, indeed the past few years, cannot continue. There is too much to be done for anyone to spend very long mourning Mr Yousaf’s departure.

And so the revolving door of UK politics turns once more. One out, one in. Rishi Sunak is the fifth Prime Minister since Brexit. Whoever replaces Mr Yousaf will be the third First Minister in just over a year. Is modern politics so demanding or are modern politicians not up to the job?

That is a question for another day. The pressing matter now is finding another First Minister. The SNP may be tempted to rush the process and go for a coronation, but haste did not serve them or Scotland well the last time.

As for Mr Yousaf, he has pledged to continue till a successor is found. Even now, one wonders if he realises what he has done. He leaves as he governed, bewildered to the end.