Scottish Labour's opposition to independence is a "fundamental" barrier for the Scottish Greens striking a Bute House style deal with the party in Holyrood, Patrick Harvie has indicated.

The Scottish Greens co-leader was speaking to the Herald on Sunday after last week launching his party's manifesto for the general election where it is standing a record 44 candidates.

But he also has a eye on the Holyrood election in 2026 where polls suggest a drop in support for the SNP and increase in Labour's.

Some polling has suggested the Greens could almost double the eight seats they won in 2021 putting the party in a position as a potential kingmaker over who forms the government.

Mr Harvie was a strong advocate of the co operation pact with the SNP believing being in power benefitted his party, enabling it to win wider support among voters.

But the Bute House Agreement, signed by the SNP and Greens in August 2021, ended acrimony in April with former first minister Humza Yousaf terminating the deal after Green grassroots members demanded a vote on whether it should continue. Days later Mr Yousaf was forced to resign.

Asked by the Herald on Sunday if he would be open to being in government with Labour, Mr Harvie pointed to a long informal process which lay behind the deal between the Scottish Greens and the SNP.

He also referred to the UK coalition government between the Conservatives and the Lib Dems, formed after the 2010 Westminster election, and how the arrangement led to the latter party having to drop campaign promises (opposition to university tuition fees).

"That level of agreement, that level of co operation that we had with the Bute House Agreement did take a long time to work towards, that trust building that was necessary took a long time to work towards.

"It also took a substantial amount of common ground, not just on the constitutional question, which is very important, but on a host of other areas as well. And even despite that we had to exclude certain issues we didn't think we were going to agree on," he said.

"I think if there was to be a change of government in Scotland - and the polls don't indicate clarity yet - every political party, mine, SNP, Labour, everyone has a responsibility to step back a bit from the numbers, and once the seats have been counted, think how best are Scotland's interests going to be served here. That doesn't necessarily mean leaping into some slightly opportunist coalition."

He added that the Lib Dems did a deal which "fundamentally gutted some of their own core campaign promises".

He continued: "If there was any scope for common ground with another party it would have to be based on honesty. From our point of view independence is part of that proposition."

Pressed on whether there could be a co operation agreement in Holyrood between the Scottish Greens and Labour, he added: "I don't think that's a likely scenario at all. Personally I would be surprised if Labour could even offer it.

"We've had successive Scottish Parliament elections where people have voted for a pro independence majority. My guess is that will continue. It's also my expectation that once people do see a thumping great Labour majority down south folk will remind themselves very quickly just how disappointed a Labour government at a UK level can be."

"So I don't think it's a likely scenario, but even if there was a more balanced parliament political parties have a responsibility to seek out the common ground, that doesn't mean you have to leap into some opportunist deal the way the Lib Dems did with the Tories.

"I don't think the Greens would ever want to do that, and obviously the constitutional dividing line is a hugely important one."

Scottish Labour was approached for comment.