The decision to seek Parliament's authority to begin the process towards an independence referendum is not one I have reached lightly.
It is therefore important to set out why we have arrived at this point – and also, in light of the significant change facing our country, to reflect on the importance of giving the people of Scotland a democratic choice over our future.
As a result of the Brexit vote, we know that change is now inevitable.
The question is what kind of change is right for Scotland. And should that be decided for us – or by us.
In the past two years or so the Scottish Government has made a number of proposals designed to protect Scotland from the impact of Brexit.
It is important to note that, had any one of these proposals been accepted by the UK Government, we would not be having this debate today.
We recognised early on the risks to Scotland from the EU referendum.
And so, before the referendum even took place, we proposed that Brexit should be possible only if all four UK nations voted to leave. That sort of provision, relatively common in federal countries such as Australia and Canada, would in this context have recognised the reality of the UK as a multinational, not a unitary, state.
That proposal was rejected.
As a result, although Scotland voted by 62% to 38% to stay within the European Union, we now face being taken out of the EU against our will – with massive implications for our economy, society and our place in the world.
Contrary to the promises made by the No campaign before the 2014 independence referendum, staying in the UK has not safeguarded Scotland's relationship with Europe – it has jeopardised it.
Before last year's elections to this Parliament, this Government took account of that possibility.
It said this: "The Scottish Parliament should have the right to hold another referendum... if there is a significant and material change in the circumstance that prevailed in 2014, such as Scotland being taken out of the EU against our will."
It's worth being clear. That commitment, combined with the result of the Scottish election – which returned to this Parliament – and then the outcome of the EU referendum, gives the Scottish Government an unquestionable democratic mandate for an independence referendum.
There is an important point here for those who seek to question that mandate. To suggest that an emphatic election victory, on the basis of a clear manifesto commitment, and a parliamentary majority on an issue does not provide a mandate, begs the question, 'what does?' – and it runs a real risk of undermining the democratic process.
Notwithstanding our mandate that we have, however, the Scottish Government did not seek a referendum on independence immediately after the EU vote.
Instead, we tried to find common ground with the UK Government.
We tried to find a way of allowing Scotland to stay in the UK while also protecting the most vital elements of our relationship with Europe.
In other words, we tried to square the UK-wide vote to leave the EU with the Scottish vote to remain – and to give effect to how people in Scotland voted in both 2014 and 2016.
We were encouraged in our endeavours by the initial comments of the Prime Minister, who made a commitment last July to seek agreement with the devolved administrations before triggering Article 50.
In the compromise paper we published in December, we argued firstly that the United Kingdom as a whole should stay inside the single market. That seemed the obvious consensus position in a state where 48% of voters – and two out of four nations – voted to stay in the EU.
Yet despite this, the Prime Minister ruled out single market membership without any prior consultation with the devolved administrations. That in itself was a breach of the commitment she made in July.
However, the Scottish Government also proposed ways in which – with political will – the option of Scotland staying in the single market, even if the rest of the UK chose to leave, might be achieved.
We also proposed significant new powers for this Parliament, short of independence, that would help protect Scotland's interests in the post Brexit landscape – powers that would effectively have delivered the federal solution that some in this Chamber say they favour.
However, all of these efforts at compromise – each and every one – have been rejected. Indeed, there has been no meaningful attempt whatsoever by the UK Government to explore these options and find common ground.
Which brings us to where we are today. Having voted to remain in the EU, we face now being taken out against our will.
The probability is that our exit – taking us outside the single market – will be on harder and harsher terms that most people, including many leave voters, would have supported in the run up to last June's referendum.
The voice of this Parliament has been ignored at every step of the way.
And, far from any indication of new powers, we now face the prospect of the UK Government using Brexit to reserve for itself powers in areas that are currently devolved to this Parliament.
All of this raises fundamental questions for Scotland.
If the UK Government can ignore this Parliament on one of the most fundamental issues that the country faces, what meaning can ever be attached to the idea that the UK is a partnership of equals?
If the UK Government refuses to guarantee the rights of EU citizens and focuses on ending free movement, despite the fact that growing our population is economically essential for Scotland – what does that mean for Scotland's desire to be an open, inclusive, welcoming society?
If the UK Government is determined to leave the single market despite the wealth of evidence that doing so could permanently weaken our economy, risking jobs, investment and trade, what does that mean for our living standards and our future prosperity?
It becomes clear that Scotland faces a fundamental question.
It is a question not just of how we respond to Brexit – but about what sort of country we want Scotland to be.
The answer to that question is surely one that should lie in our own hands.
And that is the fundamental point at the heart of today's debate.
As a country, we cannot avoid change. But we can choose what kind of change we want.
Now, let me say quite clearly that I understand why many people do not relish the prospect of another referendum on a major issue within the space of a few years. That is something that weighs heavily on me, as I am sure it does with others.
However, the alternative to planning now to give Scotland a choice, is this:
It is to simply drift through the next two years, crossing our fingers, hoping for the best, while fearing the worst.
Knowing that, no matter how hard we work to avoid it, we may well have to accept a hard Brexit, come what may – no matter how damaging it turns out to be.
It would mean accepting now that at the end of this process we will not even have the option of choosing an alternative path – that the direction of our nation will be decided for us.
I do not consider that to be right or fair. The future of Scotland should not be imposed upon us – it should be the choice of the people of Scotland.
Which brings me to the question of the timing of a referendum.
As a matter of principle, the timing – together with decisions on the franchise and, subject to the advice of the Electoral Commission, the question – should be for this Parliament to decide, just as it was in 2014.
But that decision should be taken in the interests of the Scottish people having an informed choice – not driven by a consideration of what is convenient for any politician or party.
The Prime Minister has said that now is not the time. And I agree with that.
The choice must be informed.
That means it should not happen before the terms of Brexit are known.
In the speech she gave at Lancaster House in January, the Prime Minister said this, and I quote: "I want us to have reached an agreement on our future partnership by the time the two-year Article 50 process has concluded."
If the Prime Minister is to deliver on that commitment, the terms of that agreement will require to be clear around six months in advance – autumn next year – to allow for the process of EU ratification.
The European Commission has itself said that there will be only 18 months for negotiation.
That has led to my view that the earliest time at which Scotland could make an informed choice would be the autumn of next year.
However, it is also important that the choice is made while it is still possible, in a timely manner, to choose a different path.
Therefore, it is also my judgment that the latest date for that choice to be made should be around the time that the UK leaves the EU, in the spring of 2019.
That is the timeframe that I am asking Parliament to endorse today.
But let me make this clear – if the UK Government disagrees with that timeframe, then they should set out a clear alternative and the rationale for it.
And as I have said in recent days, I am – within reason – happy to have that discussion to see if we can find common ground that I could then propose to Parliament.
However, it will simply not be acceptable for the UK Government to stand as a roadblock to the democratically expressed will of this Parliament.
It is of course entirely legitimate for the UK Government – and other parties in this Chamber – to robustly oppose independence. That is an honourable position, albeit one that I disagree with.
However, in the circumstances we now face, for the UK Government to stand in the way of Scotland even having a choice would be, in my view, wrong, unfair and utterly unsustainable.
Presiding officer, let me now turn to the nature of that choice.
I have already acknowledged that it must be an informed choice.
That means that the people of Scotland need to know the terms of Brexit, and be in a position to make an assessment of the pros and cons, before making that choice.
And it also means they need to understand the implications and opportunities of independence – whether on the economy, currency, Europe or the many other matters that people have questions about.
Those of us who advocate independence have a responsibility to consider a range of issues in light of the changed circumstances brought about by Brexit – circumstances we did not choose to be in – and then present that information in a clear way.
That is exactly what we will do – and we will do so in good time to allow scrutiny and debate well in advance of a referendum that is, at the earliest, 18 months away.
And, by doing so, we will allow people to make a genuinely informed choice between being taken down a hard Brexit path or becoming an independent country, able to chart our own course.
And that will be in stark contrast to the EU referendum. Not only was there no detail and no answers before that vote, that remains the case – shamefully so – nine months after that vote.
Presiding Officer, let me seek to end on a note of consensus.
We may differ on the best way forward, but I suspect that almost all of us – across the parties – can agree that we would rather not be in this situation.
The majority of us wish that the UK as a whole had chosen to remain within the EU. And we wish that the UK Government was pursuing continued single market membership.
But we cannot avoid or ignore the consequences of the UK-wide vote, or of the UK Government's response to it.
My determination at all times since 23 June has been to stand up for Scotland's interests. That is why I have spoken up for the rights of EU nationals, it is why I proposed single market membership for the UK as a whole, and it is why I worked hard to secure a compromise solution for Scotland.
The support of this Parliament for those proposals has been welcome.
However, nine months on, there is no indication at all that this Parliament's voice has carried any weight at Westminster.
Instead, the UK Government is taking decisions, entirely unilaterally, that I – and many others – believe will deeply damage Scotland's economy, our society and our standing in the world.
Whether we like it or not, Scotland again faces a fundamental decision about what sort of country we want to be.
The question before this Chamber today is simple: who gets to make that decision? The answer to that question cannot be me and it cannot be the Prime Minister.
The decision about what kind of country we are and what path we take can only be made by the people of Scotland.
It is for that reason that I ask members to support the motion before us today.
Phone: 0300 244 4000
The Scottish Government
St Andrew's House