The transcript of her speech in full:
Before the end of this month - and very possibly as early as tomorrow - the Prime Minister will trigger Article 50 of the Lisbon Treaty, setting the UK on course to leave the EU in March 2019.
It is important, therefore, for me to report now on the Scottish Government’s attempts to find compromise with the UK government and set out our plan to protect Scotland’s interests.
Right now, Scotland stands at a hugely important crossroads.
We didn’t choose to be in this position.
In common with most people across the country, I wish that we weren’t in this position.
But we are and the stakes are high - so we must have a plan for the way forward.
For better or worse - depending on your point of view - the future of the UK looks very different today than it did two years ago.
As a result of the Brexit vote we face a future, not just outside the EU, but also outside the world’s biggest single market.
In addition, and after a period which has seen the establishment of the Scottish Parliament and, more recently, hard won extensions to its responsibilities, we now face the prospect of a centralization of power at Westminster.
Indeed, the Prime Minister herself has been clear that the Brexit process will see the UK government reserve for itself powers in areas that are currently wholly devolved to the Scottish Parliament.
All of this has massive implications for Scotland.
It has implications for our economy: for jobs, opportunities, public spending, and living standards - and for our ability to protect and advance our vital day to day priorities in education, health and business.
It has implications for our society - how open, welcoming, diverse and fair we will be in future?
And it has implications for our democracy - to what extent will we be able to determine our own direction of travel, rather than having that decided for us?
In short, it is not just our relationship with Europe that is at stake.
What is at stake is the kind of country we will become.
Now, at times of change and uncertainty, the instinct to do nothing and just hope for the best is understandable.
But, in my view, it is not the right one.
At times like these, it is more important than ever to have a clear plan for the way ahead - to try, as far as is possible, to be in control of events and not just at the mercy of them.
That is what I have always done. It is what I have tried to do since the day after the EU referendum last year. And it is what I am determined to continue to do.
Since last June, my focus has been on trying to find an agreement with the UK government , an agreement that would reconcile the UK wide vote to leave with the Scottish vote to remain.
I was encouraged in this approach by the Prime Minister’s commitment last July to seek agreement with the devolved administrations on a UK wide approach before triggering Article 50.
The Scottish Government’s paper, Scotland’s Place in Europe, was published in good faith.
Our proposals represent significant compromise on the part of the Scottish Government.
We accepted that Scotland would leave the EU - despite the 62% vote to remain - but we argued that the UK should either stay in the single market or seek an outcome that would allow Scotland to do so.
And we set out how greater powers for the Scottish Parliament could help protect Scotland’s interests in a post Brexit landscape.
Over the past few months, we have worked hard - really hard - to try to find agreement. The Prime Minister and her government have been given every opportunity to compromise.
But today as we stand, for all we know, on the eve of Article 50 being triggered, not only is there no UK wide agreement on the way ahead - the UK government has not moved even an inch in pursuit of compromise and agreement.
Our efforts at compromise have been met with a brick wall of intransigence.
UK membership of the single market was ruled out with no prior consultation with the Scottish Government or indeed with the other devolved administrations - leaving us facing not just Brexit, but a hard Brexit.
There has been talk of special deals for the car industry and others, but a point blank refusal to discuss in any meaningful way a differential approach for Scotland.
And far from any prospect of significant new powers for the Scottish Parliament, the UK government is becoming ever more assertive in its intention to muscle in on the powers we already have.
The language of partnership has gone, completely.
And there should be little doubt about this - if Scotland can be ignored on an issue as important as our membership of the EU and the single market, then it is clear that our voice and our interests can be ignored at any time and on any issue.
That cannot be a secure basis on which to build a better Scotland.
But it is where we stand today.
Now let me stress, even at this late stage, I am not turning my back on further discussions should the UK government change its mind and decide it is willing to agree to our compromise proposals.
And, in any event, I will do everything I possibly can to ensure that Scotland’s interests are represented in the EU negotiations that lie ahead.
But I cannot pretend to the Scottish people that a compromise agreement looks remotely likely, given the hardline response from the Prime Minister so far.
That means I have to decide on the best plan to protect our interests now.
It is time for me to set out decisively and with clarity the way forward.
Doing nothing at this stage - in many ways, the easiest thing for me to do - would mean letting Scotland drift through the next two years, with our fingers crossed, simply hoping for the best.
And, of course, I do hope for the best.
I want the UK to get a good deal from the EU negotiations. That is clearly in Scotland’s interests as well as in the interests of our friends in other parts of the UK.
But I am far from alone in fearing a bad deal or indeed no deal.
Nor am I alone in fearing that even a so-called good deal will turn out to be significantly inferior to membership of the single market - and that it will set Scotland on a course that will not only damage our economy, but change the very nature of the society and country that we are.
The problem with doing nothing now is that, by the time these fears are realized, it will be too late for Scotland to choose a different path before the damage is done.
That would not be right or fair.
Whatever path we take, it should be one decided by us, not for us.
So let me set out the plan I intend to pursue.
First, I will continue to stand up for Scotland’s interests during the process of Brexit negotiations.
Second, I will now take the steps necessary to make sure that Scotland will have a choice at the end of this process.
A choice of whether to follow the UK to a hard Brexit - or to become an independent country, able to secure a real partnership of equals with the rest of the UK and our own relationship with Europe.
The Scottish Government’s mandate for offering this choice is beyond doubt.
Last year we were elected, with the highest share of the constituency vote won by any party in the history of devolution, on a manifesto that said this:
“The Scottish Parliament should have the right to hold another referendum...if there is a significant and material change in the circumstances that prevailed in 2014, such as Scotland being taken out the EU against our will.”
These conditions of course have now been met.
So I can confirm today that next week I will seek the approval of the Scottish Parliament to agree with the UK government the details of a section 30 order - the procedure that will enable the Scottish Parliament to legislate for an independence referendum.
The UK government was clear in 2014 that an independence referendum should - in their words - ‘be made in Scotland, by the people of Scotland’.
That is a principle that should be respected today.
The detailed arrangements for a referendum - including its timing - must be for the Scottish Parliament to decide.
However, in my view, it is important that Scotland is able to exercise the right to choose our own future at a time when the options are clearer than they are now - but before it is too late to decide on our own path.
Let me be clear what I mean by that.
The timing of the Brexit negotiations is not within the control of the Scottish Government.
However, we must plan on the basis of what we know now.
And what we know is that on the timetable set out by the Prime Minister, the shape of the Brexit deal will become clear in the autumn of next year - ahead of ratification votes by other EU countries.
That is therefore the earliest point at which a referendum would be appropriate.
However, it is just as important that we do not leave it too late to choose a different path in a timely way.
If the UK leaves the EU without Scotland indicating beforehand - or at least within a short time after it - that we want a different relationship, we could face a lengthy period outside not just the EU but also the single market. That could make the task of negotiating a different future much more difficult.
These considerations lead me to the conclusion that if Scotland is to have a real choice - when the terms of Brexit are known, but before it is too late to choose our own course - then that choice must be offered between the autumn of next year, 2018, and the spring of 2019.
The third - important - aspect of planning ahead is this.
I have already said that by the time a choice comes to be made, there must be greater clarity about Brexit and its implications for us.
It is just as important that there is clarity about the implications of independence. And there will be.
We will be frank about the challenges we face and clear about the opportunities independence will give us to secure our relationship with Europe, build a stronger and more sustainable economy and create a fairer society.
Scotland’s choice must be informed and up to date.
There is a great deal of talk - by all of us - about mandates from the referendums in 2014 and 2016. And, of course neither of those results can - or should - be dismissed.
But the fact is they tell us only so much about the circumstances we find ourselves in now.
In 2014, we didn’t know the UK would vote to leave the EU - had we done so it is likely that some, perhaps on both sides, would have come to a different decision.
And in 2016, independence was not on the ballot paper. We cannot simply assume that because someone voted to Remain in the EU that they would vote for an independent Scotland.
What Scotland deserves, in the light of the material change of circumstances brought about by the Brexit vote, is the chance to decide our future in a fair, free and democratic way - and at a time when we are equipped with the facts we need.
It is - above all - about informed choice.
We know that Brexit has made change inevitable. The option of ‘no change’ is no longer available.
However, we can still decide the nature of change.
Having Scotland’s referendum - at a time when the terms of Brexit are known - will give the Scottish people a choice about the kind of change we want.
And it must be a choice for all of us.
I know there are some who want me to rule out a referendum completely or delay the decision until much further down the line.
I understand why some take that view. And of course these views weigh heavily on me.
But so does this. And this, for me, is a key consideration.
If I ruled out a referendum, I would be deciding - completely unilaterally - that Scotland will follow the UK to a hard Brexit come-what-may, no matter how damaging to our economy and our society it turns out to be.
That should not be the decision of just one politician - not even the First Minister.
By taking the steps I have set out today, I am ensuring that Scotland’s future will be decided not just by me or the Scottish Government.
It will be decided by the people of Scotland.
It will be Scotland’s choice.
And I trust the people to make that choice.