HUMZA Yousaf’s decision to suddenly boot the Scottish Greens from government may have seemed incomprehensible to some observers of and actors in the nation’s political scene.

The Greens themselves were stunned to be ejected from government and many have questioned the rapidity with which Yousaf turned on his former partners.

But the decision seems to have been brewing for some time and sources close to the First Minister stress he came to the decision himself.

Kevin Pringle, a special adviser to the First Minister, has been arguing against Bute House Agreement, as it was, since at least this time last year.

A former key player in Alex Salmond’s (below) government, Pringle is respected and viewed as a serious operator in Scottish politics.

The National: Alex Salmond

In a New Statesman profile of Pringle following his re-entry to government last year the special adviser is described as being “more pragmatic and hard-headed than most of those working in the government”.

He is praised for his past record in government and for his nearly 10 years’ experience in the private sector.

The author of the piece, Chris Deerin, also interviewed Yousaf for the story, with the First Minister quoted as saying he would keep the SNP’s deal with the Greens “under regular review”.

Yousaf added: “If I ever thought it wasn’t in the party’s best interests then we’d take that decision to end the co-operation agreement.”

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It was published in October last year and ends with the words: “So far, I’ve been pretty impressed by some of the rhetoric coming from Yousaf [below].

"I’d like to believe he will live up to it, but action is always harder than words. Pringle will just have to keep pushing.”

The National: Humza Yousaf

Pringle has been publicly pushing against the Greens deal since April. In a piece for The Courier he said his party were “overvaluing” the Bute House Agreement and said SNP MSPs viewed it as “sacrosanct”.

He added: “Looked at from a longer perspective, minority government has worked well for the SNP – and for Scotland.

“During the two parliaments when the SNP formed minority administrations – 2007-11 and 2016-21 – the party advanced at the subsequent election.

READ MORE: Inside the room as Humza Yousaf sacked the Scottish Greens from government

“Indeed, when Mr Salmond led an extremely minority government (with only 47 MSPs out of 129) the SNP did so well that it went on to win an overall majority within a proportional representation voting system.”

He went on to say that “on balance” he remained supportive of the deal but added he did not think “it should be regarded as an absolute”, adding: “The Bute House Agreement wasn’t carved on tablets of stone.”

Pringle explains that he believes that the experience of being in government “would change the Greens […] for the better”.

He added: “Politicians who have served in government will form a better opposition, which in turn should make for a better government.

“Today it’s the SNP and Greens in power. It will change again in future.”

The future has come sooner than Pringle may have predicted.