By Elisabeth O'Leary
EDINBURGH (Reuters) - Scotland is almost certainly headed towards a new independence referendum after the UK triggers the process to leave the European Union, according to a lawmaker for the Scottish Greens, who back the devolved nationalist government on independence.
"I'm 85 or 90 percent sure at least that we're heading towards another referendum," Ross Greer, 22, told Reuters on Monday. He thought a decision would be made in the Spring.
Greer was a key figure in the 2014 independence campaign in which Scots voted to stick with the UK by a 10 point margin.
His party's six seats in the Scottish parliament complete the 65 seats for a majority needed by Nicola Sturgeon's Scottish government.
He said the UK government had been unwilling even to consider what compromise options might be open for Scotland, where voters opted to stay inside the EU at last June's referendum.
"That leaves us in a position of polar opposites: we can either be part of hard Brexit which tilts towards (President) Trump's America or we can be part of the European family as an independent state," he added.
British Prime Minister Theresa May has said she plans to trigger the process of leaving the EU by the end of March.
Sturgeon's government presented an alternative plan for Scotland, including continued membership of the EU single market, in December.
A source at the Scottish government noted Greer was speaking for his own party, and said the Edinburgh administration was concentrated on getting progress on that plan.
The Scottish government has insisted, however, that Scots must have all options open to them as Brexit takes shape.
The British parliament, which is sovereign, could block another referendum on independence in the national parliament. But to do so would likely provoke a constitutional crisis if opinion polls were to show most Scots favoring a ballot, or may even win over some Scots to the cause of independence.
Greer believes the decision on a new referendum will be taken this spring, in order to give time for a campaign to be prepared and a vote to take place within the two-year leaving window.
"If the vote itself is to occur ahead of Brexit ... that (campaign) process all needs to start quite soon or it becomes very, very tight," he added.
Polls, however, do not indicate that there is support for another potentially divisive vote on Scotland's future so soon after the last one and after the Brexit vote, even though most Scots are unhappy about leaving the EU.
But Greer, Scotland's youngest-ever lawmaker, argues that the vote can be won because of the new circumstances after Brexit.
He noted the 2014 independence campaign started out with support for secession at below 30 percent but rose to 45 percent by the time the vote took place.
"For us to be starting from 45 pct this time is miles ahead of last time and puts us in a much stronger position."
(Editing by Stephen Addison)