She said she wanted an “indisputably lawful” referendum to take place, arguing that her opponents would challenge the Scottish Government’s proposal in the courts if she did not go to the judiciary herself.
Ms Sturgeon said that in the event the court ruled that her proposals are outside the legislative competence of the Scottish Parliament, the next general election will become a “de facto referendum”.
The UK Government has consistently said it is opposed to a Section 30 order which would grant Holyrood the power to hold another referendum.
She said that the lawfulness of the referendum “must be established as a matter of fact, not just opinion”.
She said: “Otherwise, as we have seen again in recent days, opposition parties will just keep casting doubt on the legitimacy of the process, so that they can avoid the substantive debate on independence.”
The Scottish Independence Referendum Bill proposes a “consultative, not self-executing” referendum, she said, claiming it had the same legal status as the vote in 2014.
To applause from the SNP members in the chamber, Ms Sturgeon said: “I can announce that the Scottish Government is proposing that the independence referendum be held on October 19 2023.”
She continued: “We know that legislative competence can only be determined judicially.
“And we know that for as long as there is no judicial determination, opinions will differ and doubt will continue to be cast on the lawful basis for the referendum.
“That benefits only those parties opposed to independence.”
Ms Sturgeon said the Lord Advocate Dorothy Bain, the Scottish Government’s chief legal officer, had referred the matter to the Supreme Court.
The Scottish Government’s Bill proposes the same wording of the referendum question as in 2014.
She continued: “The process for serving the requisite paperwork on the UK Government by lawyers and messengers at arms is underway.
“And I can confirm that the reference will be filed with the Supreme Court this afternoon.”
Opposition MSPs laughed after she said: “It is of course possible that the Supreme Court will decide that the Scottish Parliament does not have power to legislate, even for a consultative referendum.
“To be clear, if that happens, it will be the fault of Westminster legislation, not the court.”
She said if such a judgment is issued, then “any notion of the UK as a voluntary union of nations is a fiction”.
The First Minister said: “If it does transpire that there is no lawful way for this parliament to give the people of Scotland the choice of independence in a referendum and if the UK Government continues to deny a Section 30 order, my party will face the UK general election on this single question: should Scotland be an independent country?”
Ms Sturgeon said this would make the next general election a “de facto referendum” if the court ruled against her.
The First Minister concluded her speech by saying: “With hard work and the independence to chart our own course, Scotland will prosper, and the people of Scotland have told us, all of us in this chamber, that they want the right to decide.”