Alex Salmond has accused the Scottish Greens of “being lukewarm on green politics.”

The former first minister also said Patrick Harvie and Lorna Slater were “more attached to office” than they were tackling climate change.

The criticism of the junior partners in the Scottish Government comes ahead of the expected abandoning of key climate targets.

Màiri McAllan, the SNP Cabinet Secretary for Wellbeing Economy, Net Zero and Energy is due to update MSPs later today on the government’s response to a damning report which warned flagship pollution commitments were “no longer credible.”

The minister is widely expected to announce that the bid to reduce carbon emissions by 75%by 2030 is now unachievable.

It is also expected that Ms McAllan will scrap the yearly targets.

Speaking to the BBC, Mr Salmond pointed to comments made by Humza Yousaf in December when the SNP leader said it was “completely unforgivable for the UK, for the Prime Minister in the face of complete climate catastrophe… to roll back on commitments to reach net zero.”

He said it was “hugely embarrassing for the First Minister.

"But it's a humiliation for the Scottish Greens. I mean, we knew already that the Scottish Greens were lukewarm on independence, now it appears they're lukewarm on green politics as well.

"So it's a great and utter humiliation. It will cause great tension."

Mr Salmond continued: "Well looking at the Green ministers, they seem to be more attached to office than they do either to independence or to green politics.

"But the key to this is to link the achievements of Scotland's greenhouse gas emission targets, being the cleanest country in the world to the delivery and political power that independence brings.

"That's the key to achievement. If we continue in the union, then both the Greens and the SNP will have continual embarrassment."

Mr Salmond’s Alba and the Greens have already clashed in recent weeks over a pro-independence rally in Glasgow.

Organisers told the former first minister that his party cannot take part as the Scottish Greens “will not share a platform” with them.

Believe in Scotland has billed their march on Saturday as a “festival of independence”, celebrating “everything about the country we want to build and sharing our positive vision for an independent Scotland.”

Speakers include First Minister Humza Yousaf and Green MSP Ross Greer, as well as Hue and Cry frontman, Pat Kane and filmmaker Jane McAllister.

Mr Salmond told the BBC: “This is because of the disagreement on self identification and women's rights. We're in favour of women's rights. We're against self-identification, the Greens took a different view, and therefore they won't share a platform on independence.

"Now, It is ridiculous of course. All independence parties should be cooperating together and putting aside the differences on other issues.

"Of course, luckily, there are plenty of other platforms, the All Under One Banner rally where Kenny MacAskill will be speaking next month and indeed the Hope Over Fear rally in September, which marks 10 years since the referendum, where I'll be speaking.

"So there's plenty of other cross party platforms. But the Green Party, as I say, is not just lukewarm on independence, today we found out they're lukewarm on green politics as well."

The Scottish Greens have been approached for comment.