The Scottish Government will publish a Bill for a second independence referendum within days, First Minister Nicola Sturgeon has announced.
She said the move is necessary so Scots can reconsider the issue in light of the vote for Brexit and "to do so before the UK leaves the EU".
She told delegates at the SNP conference in Glasgow that an Independence Referendum Bill is to be published for consultation by her Government next week.
She also used her opening speech to send a firm message to British Prime Minister Theresa May, telling her: "If you think for one single second that I'm not serious about doing what it takes to protect Scotland's interests, then think again.
"If you can't - or won't - allow us to protect our interests within the UK, then Scotland will have the right to decide, afresh, if it wants to take a different path."
Almost two-thirds (62%) of Scots voted to Remain part of the European Union, and Ms Sturgeon told the British Prime Minister: "Scotland didn't choose to be in this situation - your party put us here."
While Scots rejected independence in the referendum in September 2014, the SNP leader said in the run-up to that vote that Westminster leaders had insisted Scotland was "an equal partner in the UK".
But in the wake of the European referendum in June, she said the moment has now come to prove it.
Ms Sturgeon told the conference: "I am determined that Scotland will have the ability to reconsider the question of independence - and to do so before the UK leaves the EU - if that is necessary to protect our country's interests.
"So I can confirm today that the Independence Referendum Bill will be published for consultation next week."
The First Minister insisted a fresh vote on independence would not simply be a re-run of the arguments of 2014 - when voters backed staying in the UK by 55% to 45%.
She told SNP activists: "When Scotland does come to take this decision again - whenever that might be - we must not take for granted how anyone will vote.
"It will be a new debate, not a re-run of 2014. We must not assume that people's views - yes or no - are the same today as they were two years ago.
"Instead we must engage the arguments with a fresh eye and an open mind. The case for independence will have to be made and won."
But she said if the choice is between "an inward-looking, insular, Brexit Britain governed by a right-wing Tory party obsessed with borders and blue passports at the expense of economic strength and stability" and a "progressive, outward looking, internationalist Scotland", then it is a case that "we will win".
Ms Sturgeon insisted a "hard Brexit", which takes the UK out of the European single market, would "change the UK fundamentally", leaving the country "isolated, inward looking, haemorrhaging jobs, investment and opportunities".
Such a country "will not be the same country that Scotland voted to stay part of in 2014", she said.
"If that's the insecure, unstable prospect we face as part of the UK, then no-one will have the right to deny Scotland the chance to choose a better future."
The First Minister insisted there "is no rational case" for taking the UK out of the single market, and that the Tories have no mandate to do so.
If that does happen, she said the British Treasury has estimated the cost to the UK's economy could be as much as £66 billion, adding: "Here in Scotland 80,000 jobs could be lost. Wages would be hit by up to £2,000 and growth in the economy would slow."
She accused Mrs May of having displayed "disregard for Scotland's democratic voice that was reminiscent of Margaret Thatcher".
The SNP leader added: "High-handed pronouncements that dismiss Scottish opinion might delight the Tory party conference - but they are no longer acceptable to mainstream Scotland."
Ms Sturgeon told the conference that SNP MPs at Westminster will vote against the "Brexit Bill" when it comes before the House of Commons next year.
She said: "That Bill will repeal the legislation that enacted our EU membership. Scotland didn't vote for that and so neither will our MPs."
But she also said the SNP would "work to persuade others - Labour, Liberals and moderate Tories - to join us in a coalition against a hard Brexit".
And she said: "We will also assert the right of the Scottish Parliament to have its say."
Ms Sturgeon described Holyrood as being the "democratic heartbeat of our nation".
She added: "To deny it the right to give or withhold its consent on an issue of such magnitude would be an act of constitutional vandalism. It is not on."