Six Green MSPs with just 107,000 votes between them hold the key to the future of the union as it emerged they have the power to give Nicola Sturgeon a majority in the Scottish Parliament.
Without the backing of the small group of politicians the First Minister does not have a majority in Holyrood and could be blocked from triggering a second independence vote.
The six MSPs include Ross Greer, the youngest MSP in the Scottish Parliament at just 22, who said in February that his party would have equal say in whether a second vote should be triggered because of their importance to the First Minister.
The other five Green MSPs will also back the referendum call, although the party has vowed to secure a million signatures on a petition backing it before they do so officially.
Scottish Conservative MSP Murdo Fraser was reprimanded in the Scottish Parliament yesterday after referring to the Scottish Greens as "lentil-munching sandal-wearing watermelons".
The party holds a much greater influence than its 107,000 votes suggest and the Tories in Scotland have previously warned that the Greens should stay out of the independence debate and focus instead on making Brexit a success.
Mr Greer was the Communities Co-ordinator at Yes Scotland and a key voice in the campaign to allow 16 and 17 year olds the vote.
He left university in order to take up a position with the Yes campaign and has fought ever since for a second referendum.
In February this year he told a Scottish newspaper that a second independence vote would be called "within weeks" and called on people to begin the campaign ahead of the official launch in a bid to ensure the Yes side gets a head start.
Speaking to the Sunday Herald he said: "People out there are champing at the bit it to get started". He added: "A decision to call the referendum would be a joint decision of the SNP and the Greens.
"In calling a referendum the SNP as the Government would have to come to parliament and make that announcement. That's not just their right, it's their responsibility as the Government. "But it's a collective decision based on parliamentary arithmetic."
There are five other members of the Scottish Green party who will play a decisive role in the decision to push for a second vote on whether Scotland should leave the union.
Patrick Harvie, John Finnie, Mark Ruskell, Alison Johnstone and John Wightman make up the rest of the group.
One of the number, Mr Finnie, defected from the Scottish National Party after the first independence vote in protest at the party's vow to rejoin Nato if Scotland had broken away from the rest of the UK.