According to BBC News, if all goes according to the two-year plan of negotiations, then Brexit will happen in March of 2019. Scottish voters backed remaining in the European Union, and Sturgeon said Scotland mustn't be "taken down a path that we do not want to go down without a choice".
"That is what the Liberal Democrats strongly believe and we will spend the next two years saying so".
"I don't think there are many countries that would have anything critical to say of such a deal as they would be helped by it", he added.
"I have set out my objectives".
His predecessor, Sir Ivan Rogers - who quit abruptly in January, condemning the Government's "muddled thinking" - warned it would take until the mid-2020s to achieve a free trade deal. They include putting issues like continuing working together on issues like security at the core of what we are doing. "We are ready to begin negotiations".
Once Article 50 is triggered, Council President Donald Tusk is expected to provide an initial response to the Prime Minister within 48 hours, and the remaining European Union 27 countries will then put together a timetable for negotiations on the UK's withdrawal to take place.
Stephen Gethins, the SNP's Europe spokesman, said: "Today's announcement that the Prime Minister will push ahead and unilaterally trigger Article 50 shatters beyond fix any notion or position that the Prime Minister is seeking a UK-wide agreement".
After 40 weeks of topsy-turvy politics since the referendum vote last June, Prime Minister Theresa May will pull the trigger by invoking Article 50 of the Lisbon Treaty.
The Article 50 process clearly stated that the European Union should take account of its "future framework" with the United Kingdom, as well as agree the exit deal.
The Prime Minister will deliver her letter triggering Article 50 to President Tusk on the Wednesday, and deliver a statement to the House of Commons announce the move.
Tusk said he would issue draft guidelines for the negotiations within 48 hours, and officials said European Union leaders are then likely to meet at a special summit in early May to approve them.
He said the Government wanted to secure "a new, positive partnership between the United Kingdom and our friends and allies in the European Union".
Meanwhile, Britain's Institute for Government has said as many as 15 new Parliamentary Bills may be needed due to Brexit.
Brexit minister David Davis has said there would be no sudden drop in numbers, as it would take years to fill low-skilled jobs in hospitality, social care and agriculture now done by immigrants.