THE Scottish Greens have admitted they are concerned about being punished at the ballot box if they form a joint government with the SNP.

Green co-leader Lorna Slater said it would be a “risk” for both parties, and the ruinous impact of a Westminster coalition on the Liberal Democrats was “on everybody’s mind”.

Nicola Sturgeon announced on Wednesday that she had embarked on talks with the Greens about coming to a “formal co-operation agreement”.

She said what the two sides hopes to achieve was “potentially ground breaking”.

Although it would stop short of a full coalition of the kind between Labour and the LibDems in Scotland from 1999 to 2007, it could see Greens entering government as ministers.

However, recent examples of joint government at Westminster have hurt the smaller party.

After the LibDems went into coalition with the Tories in 2010 and reversed their opposition to student tuition fees they were destroyed at the ballot box.

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In the 2011 Scottish Parliament election, the LibDems fell from 16 MSPs to five and have never recovered. They lost another to fall to four MSPs earlier this month.

While at the 2015 General election, the LibDems went from 57 seats to eight. They currently have 11 MPs. 

Northern Ireland’s DUP have also had a torrid time after agreeing to support Theresa May’s ill-fated minority Tory Government at Westminster from 2017 to 2019.

Talking to the PA news agency about the experience of the LibDems, Ms Slater said: “I think that’s on everybody’s mind, absolutely.

“I think both the Scottish Government and ourselves are taking a risk, as the First Minister said, to put this out there, to publicly announce that we’re interested in trying to find effective ways of tackling the climate crisis, effective ways of dealing with recovery by working more closely together.”

She added: “The kind of arrangement that we’re probably looking at doesn’t look like what we would consider a coalition.

“That’s probably not the kind of arrangement we would look at, it’s probably something that’s a bit of a distance from that, a different kind of arrangement.”

The Greens co-leader also said it was the First Minister who made the first approach, contacting both Ms Slater and Mr Harvie to invite them to talk about a potential alliance.

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While there is little known about the detail of a final agreement, Ms Slater said it could mean the creation of long-term financial planning, meaning the Scottish Government could rely on the support of the Scottish Greens in such a way as to make longer-term financial commitments in the annual budgets, rather than last minute horse-trading every year.

Both Ms Slater and Ms Sturgeon have said an agreement is not necessary because of parliamentary arithmetic, but have said it is an attempt at cross-party working.

The SNP won 64 seats at the recent election, although one MSP on sick leave, while the Greens returned eight MSPs, although one quit the party to become Presiding Officer.

Together, they represent a majority in favour of a second independence referendum, and a formal working agreement could be seen as an attempt to reinforce Ms Sturgeon’s mandate for Indyref2 in the face of resistance by Boris Johnson.

However Ms Slater, a Lothian list MSP, said she was take the SNP entreaties at face value.

She said: “I don’t think I can second guess the motivation of the Scottish Government.

“Certainly the way they’ve presented to us in the approach they’ve made has been around wanting to change their approach on climate, wanting to be seen to take that seriously, to take action on it … bring in the experts – bring in the people who have practical policies.

“I’m optimistic that means the Scottish Government are genuine in their interest to take a more serious and more integrated look – more joined-up thinking – on the climate crisis and how that depends on having a wellbeing economy.

“I’m taking it hopefully in the spirit which I think it was intended, with good intentions to really, genuinely make some transformative change.”

The Scottish Tories this week said an SNP-Green joint government would be a “disaster” for Scottish businesses, given the Green opposition to new roads, the North Sea oil and gas industry, and the party’s desire to hike taxes on the better off.