Sturgeon plans to trigger second Scotland independence vote
Scotland's First Ministersays she plans to trigger another independence referendum.
She said the vote could be held in autumn 2018 at the earliest.
Speaking at Bute House in Edinburgh, she added: "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 our own path."
Since the UK vote to leave the European Union, Ms Sturgeon has repeatedly said a second independence referendum is "highly likely".
Scots voted 62 per cent to 38 per cent to remain the EU while the UK as a whole voted to leave.
Ms Sturgeon said: "The timing of the Brexit negotiations are not within the control of the Scottish Government. However, we must plan on the basis of what we do 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."
Ms Sturgeon had called for Scotland to be given a "differentiated deal'' which would see the country remain part of the European single market through membership of the European Economic Area but said the UK Government has refused to compromise.
She said Theresa May and the UK Government had been given "every opportunity" to compromise but had "not moved even an inch".
The First Minister said appeals have been met with a "brick wall of intransigence".
Scots voted by 55 per cent to 45 per cent to stay part of the UK in September 2014. Despite that vote, the issue is far from resolved.
Following the referendum, the SNP saw a massive surge in membership, with the nationalists now the third biggest political party in the UK. More evidence of the party's popularity came in the 2015 general election when they won all but three of the 59 seats up for grabs north of the border.
In 2016 the party won a third term in power at Holyrood, although Nicola Sturgeon lost the overall majority her predecessor Alex Salmond had won in 2011.
However, the SNP manifesto for the May 2016 Scottish elections stated: "We believe that the Scottish Parliament should have the right to hold another referendum if there is clear and sustained evidence that independence has become the preferred option of a majority of the Scottish people - or if there is a significant and material change in the circumstances that prevailed in 2014, such as Scotland being taken out of the EU against our will."
Just weeks after the Scottish Parliament elections, the European Union referendum saw 62 per cent of Scots vote to remain while the UK as a whole voted to leave - the very situation outlined in the SNP manifesto.
Within hours of the result being known, Ms Sturgeon warned a second independence referendum was "highly likely".
Ms Sturgeon has already indicated the autumn of 2018 could be a "common sense" time for a referendum but there has been speculation that Downing Street may attempt to delay another vote until after Britain has exited the EU.
The Scottish Government has already carried out a consultation on a draft Referendum Bill, which sets out how a second vote on independence could be held.
Theresa May has not yet said if the Conservatives would seek to prevent a referendum from being held, by voting against a section 30 order to transfer the necessary legal power for the ballot. Instead, the Tories say simply that a second referendum should not be held.
However, a number of senior politicians at Westminster, including Labour leader Jeremy Corbyn, have said that Westminster should not seek to block a fresh vote on independence.
Within hours of the result of the 2014 referendum result being known, Ms Sturgeon's predecessor Alex Salmond had announced he would be stepping down as both SNP leader and Scotland's first minister.
While it seems certain that a second vote against independence would mean there could not be another such ballot for a considerable period of time, it is not certain that Ms Sturgeon would have to step down.
Politics expert Professor James Mitchell, of Edinburgh University, told the Press Association: "It's not as certain as some imagine that she (Ms Sturgeon) would go, that would depend on how she handles defeat.
"I think she could get away with staying on in a way he (Mr Salmond) could not have."
He argued Mr Salmond had been SNP leader for 20 years - over two spells each lasting a decade - whereas Ms Sturgeon has, in comparison, been head of the party for less than three years, taking over the role in November 2014.
In addition, Prof Mitchell said there was no obvious successor to Ms Sturgeon waiting in the wings in the party.
He said: "There's no rule she would have to go, for all sorts of reasons I don't think it would be certain."