A leading pro-independence campaign group has launched a new fundraising drive as it expects a second referendum to be called within weeks.
Business for Scotland has told supporters it is getting "back in full campaign mode" ahead of a new vote which it anticipates in May or September 2018.
The organisation focused during the 2014 referendum campaign on the economic and business case for Scottish independence.
Group founder Gordon MacIntyre-Kemp emailed members to say "we are only weeks away" from a second referendum being called, according to the Sunday Herald.
Next month will see both the triggering of Article 50 by the UK Government to begin the formal Brexit process and the SNP's spring conference in Aberdeen.
It comes after reports that the UK Government is preparing for negotiations with the Scottish Government to hold a second independence referendum in 2018.
First Minister Nicola Sturgeon said after the result of the EU referendum in June last year, which saw 62% of Scots vote to stay in the EU but a majority across the UK opt for Brexit, that another independence referendum is "highly likely".
In his email to supporters, Mr MacIntyre-Kemp said: "Business for Scotland was a vital contributor to the growth of the Yes vote in 2014.
"We need your help to renew the business and economic case for independence and drive Yes support to the levels required to call and win indyref2.
"We didn't go away, instead we have kept on campaigning for independence and we also campaigned for a Remain vote in the EU referendum.
"We are getting ready for indyref2 in May or September 2018 and so we are back in full campaign mode.
"Please back us to renew the business and economic case for independence, drive Yes support to the levels required to trigger, and then win indyref2."
The group's online fundraiser has already raised nearly a third of its £15,000 target.
Prime Minister Theresa May has said that Scotland does not want to "rerun the independence referendum".
In an opinion piece in January, May wrote: "While I respect the views of all those in Scotland who wanted the UK to remain in the EU, I do not believe that their votes represent a wish to separate Scotland from the rest of the United Kingdom or rerun the independence referendum.
"I hope it is clear that our comprehensive plan of Brexit addresses issues and concerns that have been raised in Scotland as well as across the rest of the UK."
The SNP insist that the Brexit result constitutes a "material change of circumstances" that would justify a new referendum, as outlined in the party's 2016 Holyrood manifesto.
The Scottish Government published a paper in December last year setting out options to keep Scotland in the European single market even if the UK leaves, which the UK Government said were being "studied carefully".