The SNP would be left with a “de facto” deal in place with the Scottish Greens if John Swinney succeeds Humza Yousaf to become Scotland’s latest first minister, veteran nationalist Fergus Ewing has warned.

Mr Ewing, a former member of the Scottish cabinet, claimed such an arrangement would be a “kind of Scottish Green Frankenstein”.

He branded as “disastrous” the powersharing Bute House Agreement (BHA) between the two parties, which Mr Yousaf tore up last week, precipitating his downfall as First Minister.

While senior figures in the SNP are now backing former deputy first minister Mr Swinney to be his successor, Mr Ewing said that if Mr Swinney “is to unite Parliament, as all his supporters claim he is certain to do, will we not be left with a de facto BHA in force”.

Fergus Ewing
Fergus Ewing described the Greens as ‘a fringe party of extremists’ (PA)

Mr Swinney and former Holyrood finance secretary Kate Forbes have emerged as the early front-runners as the SNP looks to appoint a new leader in the wake of Mr Yousaf’s sudden resignation on Monday.

In the hunt for a successor, Mr Ewing insisted the Greens should not be given too much influence.

Writing in the Scottish Daily Mail, Mr Ewing, who has repeatedly spoken out against the Greens, insisted: “The green tail has been allowed to wag the dog for too long.

“Last week, it was docked. But this week, it has re-emerged as a kind of phantom limb.”

Neither Mr Swinney nor Ms Forbes – who came a close second to Mr Yousaf in the 2023 SNP leadership contest – have yet confirmed if they will put themselves forward.

But with the SNP short of an overall majority at Holyrood, support from the Greens could still be crucial to whoever succeeds Mr Yousaf.

The smaller pro-independence party made clear during the 2023 leadership contest that seven MSPs would not work with Ms Forbes, who suffered a backlash after revealing she would not have supported same-sex marriage legislation if she had been a parliamentarian when it was voted on.

Former Scottish finance secretary Kate Forbes is still considering if she will run again for the SNP leadership (Andrew Milligan/PA)

Mr Ewing said: “If the reason we must choose ‘Honest John’ is because the Greens will support him, and that we must not support Kate Forbes because the Greens don’t based on her religious beliefs, have we handed them the pen to undersign their preferred candidate as leader of the country?

“People are appalled a fringe party of extremists should continue to wield such power and influence, albeit because the SNP leadership choose to yield it to them.”

Speaking in support of Ms Forbes, he added: “Kate sees the urgent need to reset our politics to provide fresh hope and to focus on competent government, the pressing need to spend our time in government working with business to build economic success and prosperity over a period of 10 years, not just a short-term fix.”

However he said Mr Swinney “remains in thrall to the Green experiment”.