A slim majority of Scots now support independence, bolstered by the support of those who previously rejected a split from the United Kingdom but who now back it because of their opposition to Brexit, according to a poll published on Thursday.
The survey found that 51% supported independence, YouGov said, the first time the pollster had found majority backing for a "Yes" to secession since 2015.
Scotland's nationalist First Minister Nicola Sturgeon wants to hold another referendum but British Prime Minister Boris Johnson has refused permission, and no vote can take place without the consent of the government in Westminster.
In 2014, Scots voted to remain in the United Kingdom by 55% to 45%. However, members of Scotland's parliament on Wednesday voted in favor of a new poll, arguing that Britain's impending departure from the European Union, which a majority of Scots opposed, had changed the circumstances.
The poll found that more than one in five of those who voted "No" in 2014 but backed staying in the EU would now back independence.
However, a majority of Scots opposed holding a second vote on the issue this year and the survey found that many voters were still worried about the economic impact, with 42% thinking an independent Scotland would be worse off against 35% believing it would be better off.
"These are concerning times for unionists both north and south of the border with 'Yes' gaining considerable ground on 'No' since 2014," said Chris Curtis, Political Research Manager at YouGov.
"Yet the fundamental problem that flummoxed the 'Yes' movement in 2014, that independence would damage the economy, still exists and could still set them back in indyref2."
Since the 2014 vote, most polls have suggested that Scots would narrowly reject independence again.
However Sturgeon's Scottish National Party, which strongly opposed Brexit, won 48 of Scotland's 59 seats in Britain's national election in December, taking 45% of votes cast, an 8 percentage-point increase from 2017.