SCOTTISH Greens co-convener Patrick Harvie yesterday warned it was time for Yes supporters who identified with "the 45" to leave the label behind.

Addressing 400 activists at his party's biggest-ever conference yesterday, the Glasgow MSP said it was vital to reach out to No voters and co-operate with others rather than focus on an increasingly meaningless dividing line.

To underscore the point, Harvie said he was delighted and excited to welcome former SNP MSP John Finnie as the party's newest recruit.

Finnie, who left the SNP in 2012 when it reversed its longstanding opposition to Nato membership, received a standing ovation from the packed hall at Napier University in Edinburgh.

"The language of the Green Party is the language of social justice and environmental justice, and I am proud to be associated with it," he said.

Finnie hopes to stand for election as a Green candidate at the 2016 Scottish election, but will continue to sit as an Independent MSP for the Highlands and Islands until then.

In the opening address of the two-day gathering, Harvie said it was hard to overestimatethe positive effect caused by the trebling of the party's membership from around 1700 to more than 6300 since the referendum last month.

He said: "Let's be honest. We have been a small party for too long. It's not enough to be convinced that we are right and be a small political party on the fringes."

A former board member of the Yes Scotland campaign, Harvie said he wanted to maintain the energy and ideas seen in the referendum, but stressed the need to move on from the ballot.

He said: "I know there are many people who are still very proud of being part of the 45% who voted Yes. And there are some who are finding it difficult to accept it wasn't a win.

"But I think it's important to say that this dividing line between the 45% and the 55% is one we're going to have to move beyond.

"Unless we can reach beyond that dividing line I think we will have failed to capture the energy that does remain possible in the country. That dividing line is one that isn't relevant for us as individuals any more, it isn't helpful for the party, and I think it would be damaging for Scotland as well to obsessively focus on that dividing line for the future."

Referring to the Smith Commission on more powers for Holyrood, he warned that if it ended in "a traditional party stitch-up, we will have betrayed the trust of the whole electorate".

He said the Unionist parties already seemed to be "rolling back" on their earlier positions, and "forgetting the much more radical forms of devolution" promised late in the referendum.

Harvie said Scotland should have significant powers over tax, spending and borrowing, or it would merely be implementing the austerity agenda on Westminster's behalf.

He also demanded a welfare state worthy of the name, not a "humiliation state" bullying people into low-paid jobs and subsidised poverty wages.

Electorally, Harvie said the Scottish Greens would focus on adding to the party's two MSPs at Holyrood in 2016, but for next May's General Election the effort and money should go into securing the re-election of the UK's only Green MP, Caroline Lucas.

Harvie also launched a crowdfunding initiative to help fight both campaigns.

He said the Tories would create a meaner and harsher society if returned to power next year, while Labour was now a tragic party which no longer knew what it stood for, unable to offer an alternative to Coalition cuts.

Referring to the election of Ukip's first MP last week in Clacton, he said it was a nauseating sight for Ukip leader Nigel Farage, "a wealthy, right-wing merchant banker", to be touted as an anti-establishment choice.

"We can't allow these people to be the story of next year's election," he said.

Speaking afterwards, Finnie said: "I've been a Green all my life; I just didn't know it. Working and campaigning alongside Greens, I've seen that my values are Green values - social and environmental justice, democracy and integrity, internationalism and peace. Receiving my membership card today feels like a homecoming.

"I have no ill will towards the SNP, a substantial minority of whom voted with me to oppose Nato membership. But the project of building a fairer and more sustainable Scotland isn't the exclusive property of one party, or even any group of parties, and I would urge others who share my views to take the next step and join the Greens as I have done."