Countdown is on: Britain will begin EU exit March 29

LONDON — Britain will begin divorce proceedings from the European Union on March 29, starting the clock on two years of intense political and economic negotiations that will fundamentally change the nation and its European neighbors.

Britain’s ambassador to the EU, Tim Barrow, informed European Council President Donald Tusk of the exact start date Monday morning.

“We are on the threshold of the most important negotiation for this country for a generation,” Brexit Secretary David Davis said. “The government is clear in its aims: a deal that works for every nation and region of the U.K. and indeed for all of Europe — a new, positive partnership between the U.K. and our friends and allies in the European Union.”

The trigger for all this tumult is the innocuoussounding Article 50 of the EU’s Lisbon Treaty. British Prime Minister Theresa May, under the Article, will notify Tusk of her nation’s intentions to leave the 28-nation bloc.

The article stipulates the two sides will have until March 2019 to agree on a divorce settlement and — if possible — establish a new relationship between Britain, the world’s No. 5 economy, and the EU, a vast single market containing 500 million people.

The European Commission — the bloc’s legislative arm — said it stood ready to help launch the negotiations.

“Everything is ready on this side,” commission spokesman Margaritis Schinas said.

Leaders of the 27 other EU nations will meet by May to finalize their negotiating guidelines.

But like any divorce, things might not go to plan.

The letter May sends next week will plunge Britain into a period of intense uncertainty. The country doesn’t know what its future relationship with the bloc will look like — whether its businesses will freely be able to trade with the rest of Europe. Those things have become part of life in the U.K. since it joined what was then called the European Economic Community in 1973.

It’s also not clear what rights the estimated 3 million EU citizens working and living in Britain will retain.

Matt Dunham / Associated Press The Union Jack flies in front of Big Ben, which has marked British history since 1859 and will witness more as the country faces uncertainty.