Nicola Sturgeon has said she will make an "important" speech today before the UK Government begins the formal process of leaving the EU.

It comes amid reports that Scotland's First Minister is to try to "derail" Brexit by outlining plans for a second independence referendum.

The Daily Telegraph said she could name the date for a referendum, if Prime Minister Theresa May does not agree to her wishes.

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Ms Sturgeon has previously hinted that autumn 2018 would be a suitable time to call a referendum.

The First Minister tweeted on Monday morning: "This morning, I'll make an important speech in Bute House ahead of the triggering of Article 50."

It will take place before a Commons vote on the Article 50 Bill later in the day.

If the Bill triggering the exit from the EU is passed, it could win royal assent as early as Tuesday, allowing Mrs May to begin the two-year Brexit process.

Ms Sturgeon is believed to want the Prime Minister to include a series of demands for Scotland to be given special treatment in negotiations, including a Section 30 order from Westminster, allowing a legally binding vote on Scotland's place in the UK to be held.

The First Minister has repeatedly warned that a fresh ballot is ''highly likely'' after Scots voted to remain in the European Union and the UK as a whole voted to leave.

A number of opposition party leaders have made clear their opposition to another ballot on the issue being held, with Scots having voted to stay in the UK by 55% to 45% in September 2014.

Labour former chancellor Lord Darling, who led the campaign against independence in 2014, warned that, alongside Brexit, a Scottish breakaway "would make a bad situation worse" and pointed to opinion polls which show that a majority of Scottish people do not want another referendum.

Countries like Spain, which has resisted Catalan and Basque calls for independence, were unlikely to allow Scotland a "carve out" to stay in the EU.

"I've always said that if there was an overwhelming demand as in 2014, the issue was there, it would have been daft to have blocked it," the peer told the BBC Radio 4 Today programme.

READ MORE: Independence would mean 'turbo-charged austerity' for Scotland, says Labour leader Jeremy Corbyn

"But at the moment we are in a situation when we only went to the polls three years ago, the result was very decisive - 55-45."