European leaders are preparing for Article 50 to be triggered this week
The risks to Britain of its vote to leave the EU were laid bare on Monday when Scotland's nationalist government announced a new independence vote in anticipation of the imminent start of the Brexit process.
Legislation empowering Prime Minister Theresa May to formally begin withdrawing from the European Union is expected to become law by Tuesday, allowing her to start Brexit at any point.
But Downing Street sought to play down speculation she would immediately trigger Article 50 of the EU's Lisbon treaty, starting the two-year divorce process.
"We have been clear that the prime minister will trigger Article 50 by the end of March," her spokesman said, heavily emphasising the word "end".
The prospect of an imminent start to negotiations to pull Britain out of the EU, after four decades of membership, was however enough to push the Scottish nationalist government into calling a fresh independence vote.
As the price for cutting immigration, May has said Britain will leave Europe's single market -- a move that the Scottish National Party (SNP) in power in Edinburgh has warned would be highly damaging to jobs and growth.
SNP First Minister Nicola Sturgeon has said since the June referendum vote for Brexit that Scotland, where a majority wanted to stay in the EU, sought a different future.
On Monday she made good on her threat, promising to give Scotland "a choice at the end of this process" .
"A choice of whether to follow the UK to a hard Brexit or to become an independent country, able to secure a real partnership of equals with the rest of the UK and our own relationship with Europe," she said in Edinburgh.
The announcement pushes to centre stage one of May's biggest concerns about Brexit, the break-up of the United Kingdom, as she prepares to start negotiations with the other 27 EU member states.
Legislation empowering the prime minister to trigger Article 50 returned to parliament for its final stages on Monday.
If approved later on Monday, it could be signed into law by the head of state Queen Elizabeth II as early as Tuesday, leaving May's path clear to begin the path to Brexit -- and an uncertain new future for Britain.
European leaders are preparing for Article 50 to be triggered this week, as is Britain's opposition Labour party.
However, speculation is growing that it may now be delayed until after a March 25 summit in Rome to mark the EU's 60th birthday -- timing that would likely be welcomed in Brussels.
Once May has notified the EU of her decision by letter, the bloc will take just 48 hours to issue its first draft proposal for the negotiations, with a follow-up meeting planned on April 6.
Talks are not expected to begin for months as both sides finalise their strategies.
EU leaders are determined that the final terms do not encourage other member states to follow Britain and jump ship.
Meanwhile Britain will be pressing to forge a new trade deal within the two-year timetable provided by Article 50, to avoid crashing out of the EU.
'Uncertainty and division'
May introduced the bill empowering her to trigger Article 50 after the Supreme Court ruled only parliament could approve the start of Brexit.
The bill was held up earlier this month by amendments passed in the unelected House of Lords, demanding guarantees for EU nationals' rights and a parliamentary vote on the final withdrawal deal.
Brexit minister David Davis urged MPs to overturn the Lords amendments in a vote on Monday, saying: "We will not enter the negotiations with our hands tied."
Sturgeon said she would next week begin seeking authority for a vote on independence between autumn 2018 and early 2019 -- ideally before Britain leaves the EU.
May condemned the idea of another referendum, saying most Scots do not want it and warning it "sends Scotland on a course for more uncertainty and division".
The British government has the power to block Sturgeon's request, but this would likely only energise the Scottish nationalists' cause.
In the first vote in 2014, Scots voted by 55 percent to reject independence. However, polls suggest any new referendum would be closer.