Brexit: What is Article 50 and when will it be triggered?

Britain voted to leave the European Union in June 2016, but negotiations cannot not begin in Brussels until Theresa May’s government triggers Article 50 of the Lisbon Treaty.

The prime minister has said this, the process by which a country begins to leave the EU, will happen at the end of March.

Meanwhile, Nicola Sturgeon, the Scottish first minister, has said she will push for a second independence referendum while negotiations are ongoing.

As the historic day approaches, we look at exactly what Article 50 is…

What is Article 50?
The Lisbon Treaty, which came into force on December 1, 2009, replacing two previous treaties, contains a get-out clause for any member state that wants to leave the European Union: Article 50. No country has taken this bold step before, and the clause is low on details. The only real requirement is that notification must be sent in writing to the President of the European Council.

When will Article 50 be triggered?
Theresa May has maintained that Article 50 will be triggered before the end of March, and now Liam Fox, the secretary for international trade, has said, rather vaguely, “it will definitely be this week or next week or the week after.” The rumours are that Tuesday will be the date the trigger is pulled.

What’s the latest?
The European Union (Notification of Withdrawal) Bill will return to the House of Commons today, after peers in the House of Lords inserted two amendments, one of which seeks to guarantee the rights of overseas EU nationals in the UK. The other argues that MPs should be given a meaningful vote on the final Brexit deal — that is, to prevent Brexit from happening if the House is not happy with the terms of the exit. However, the government expects MPs to reject the amendments, meaning it will likely return to the upper chamber this evening.

What will this mean?
The House of Lords can now either back down or continue to push for changes. If it does allow the bill to pass, it will receive Royal Assent. The government is confident it will be “done and dusted” by midnight. Theresa May will then be free to notify the European Council of Britain’s decision to leave the EU.

MORE: Brexit is going to be a big test for the union that ended ‘centuries of repeated wars in Europe’
MORE: US companies say Brexit puts 1.4 million UK jobs and $593 billion of investment at risk

So, will it be tomorrow?
On Tuesday, the Prime Minister will brief the Commons about this week’s EU summit, which, many have speculated, will be when she triggers Article 50. But, as confident as the government is, delays are possible.

When is the latest it will be triggered?
If there is another delay to the Bill, the process will likely be delayed until the last week in March to avoid clashing with the Dutch elections. May has always maintained that Article 50 would be triggered by the end of March and time is ticking. Once the European Council is notified, negotiations with Brussel regarding to the type of exit, and the trade deals Britain leaves with, can finally begin. It has two years to get the best deal possible.

What happens at the end of the two years?
The European Union says that Britain will be forced to leave with nothing if no deals are struck in the meantime, meaning time is of the essence. May’s government will be hoping for positive talks quickly. However, Lord Kerr of Kinlochard, a diplomat who devised Article 50, says it is not “irrevocable” and Britain could still change its mind once details become clearer.