MSPs are set to back calls for a new referendum on Scottish independence in a vote at Holyrood.
First Minister Nicola Sturgeon wants to hold a new poll later this year, and wants UK ministers to agree to this.
But Prime Minister Boris Johnson has rejected her call for a transfer of powers, saying the 2014 vote was a “once in a generation” event.
A vote will be held at the Scottish Parliament on Wednesday afternoon to agree “a referendum should be held”.
Ms Sturgeon is then due to make a speech on Friday setting out the “next steps” in the “campaign to secure Scotland’s future as an independent nation”.
The motion for the “Scotland’s future” debate at Holyrood asks MSPs to agree that “there has been a material change in circumstances since 2014 and that a referendum should be held so that the people of Scotland can decide if they wish to become an independent country”.
It also calls on the UK government to reach agreement “on such a referendum taking place on a date and in a manner determined by the Scottish Parliament”, noting the Scottish government’s target of this happening in 2020.
MSPs previously backed a motion calling for a fresh referendum in March 2017 by a margin of 69 to 59.
A similar result is likely this time, with the pro-independence Greens set to back the SNP – but as with the previous vote, it will not bind the UK government into any agreement.
Ms Sturgeon formally requested a transfer of powers – similar to that which underpinned the 2014 referendum – after the SNP won 48 of Scotland’s 59 seats in December’s general election.
Mr Johnson replied that he could “not agree to any request for a transfer of power that would lead to further independence referendums”.
Ms Sturgeon said MSPs should “endorse a fundamental democratic principle – that this country has the right to choose its own future”.
She said: “The significance of today’s debate should not be underestimated. It takes place just two days before Scotland and the rest of the UK are taken out of the EU, and the vote of the Scottish Parliament will be noticed around Europe and beyond.
“It is my fervent hope and belief that Scotland will rejoin the European family of nations as an equal, independent country.”
MSPs will also be asked whether to keep the European flag flying outside Holyrood, with ministers seeking to overturn an earlier decision by parliamentary authorities that it should be taken down when the UK leaves the EU.
The Scottish Conservatives criticised the SNP’s focus on the constitution, saying the party of government “isn’t even pretending to care about other issues now”.
Chief whip Maurice Golden said: “Valuable time in the Scottish parliament should be used to address the very severe problems in our hospitals or the crisis engulfing our education system.
“Instead, the nationalists want to revert to the only subject they excel in – stoking up constitutional division.”