The First Minister insisted that the route to independence must be "lawful and democratic" for independence to be achieved and that "the SNP is not abandoning the referendum route, Westminster is blocking it".
In a speech in Edinburgh following the Supreme Court ruling, she said: “The next national election scheduled for Scotland is the UK General Election, making it both the first and the most obvious opportunity to seek what I described back in June as a de facto referendum.
“As with any proposition in any party manifesto in any election, it is up to the people how they respond. No party can dictate the basis on which people cast their votes."
Nicola Sturgeon said the principle is that the SNP will look to establish majority support for independence at the next election and the "precise detail" of proposition will be put to public and a special conference will be held in the new year.
She said: “Now that the Supreme Court’s ruling is known and de facto referendum is no longer hypothetical, it is necessary to agree the precise detail of the proposition we intend to put before the country.
“Given the magnitude of these decisions for the SNP, the process of reaching them is one the party as a whole must be fully and actively involved in.
“I can therefore confirm that I will be asking our National Executive Committee to convene a special party conference in the new year to discuss and agree the detail of a proposed ‘de facto referendum’.
“In the meantime, the SNP will launch and mobilise a major campaign in defence of Scottish democracy because we should be in no doubt that, as of today, democracy is what’s at stake.”
She added "We must and we will find another democratic, lawful means for Scottish people to express their will" and that the next general election is the next and most obvious vehicle for that.
The First Minister admitted the ruling of the Supreme Court that the Scottish Parliament cannot legislate on independence without Westminster consent is a “tough pill for any independence supporter to swallow” adding ““I’m well aware that there will be a real sense of frustration today, in both the SNP and in the wider movement.
“I share that. My message though is this: while that is understandable, it must be short lived – and I believe it will be.
“Indeed, I suspect we will start to see just how short-lived in the strength of the gatherings planned for later today in Edinburgh and other parts of Scotland.”
She said the case of Scottish independence is “now essential” because of “what Westminster control means on a day-to-day basis now and for future generations”.
The First Minister added: “Without an agreement between the Scottish and UK governments, either a section 30 order or a UK Act of Parliament to change its powers, the Scottish Parliament cannot legislate for a referendum that the people of Scotland have instructed us to deliver.
“That is a hard pill for any supporter of independence, and surely indeed for any supporter of democracy, to swallow.”