Proceeding with the populist/nationalist agenda that has been sweeping the globe and which included the election of Donald Trump as President of the United States, Britain has officially filed for divorce from the EU (European Union), triggering a complete exit to be conducted over a two-year span.

LONDON (AP) — Britain formally filed for divorce from the European Union Wednesday, walking out on a 44-year relationship, enacting the decision made by U.K. voters in a referendum nine months ago and launching both Britain and the bloc into uncharted territory. The EU official has received the letter from Britain, setting off the process, reports The Washington Times.

Prime Minister Theresa May told House of Commons that she has invoked Article 50 of the EU’s key treaty, the trigger for a two-year countdown to Britain’s exit.

Just before May’s statement, Britain’s EU envoy, Tim Barrow, hand-delivered a letter from May to EU Council President Donald Tusk in Brussels.

Photos were released of May signing the letter late Tuesday in the Cabinet room at 10 Downing St., under a portrait of Britain’s first prime minister, Robert Walpole.

The letter, which is several pages long, was whisked to Brussels aboard a Eurostar train, British media reported. Barrow arrived at European Council headquarters carrying a briefcase Wednesday morning, before his appointment with Tusk. The letter was received.

May’s office said she will tell lawmakers that the U.K. is embarking on a “momentous journey” and should unite to forge a “global Britain.”

“It is my fierce determination to get the right deal for every single person in this country,” she said.

Britain’s Treasury chief, Philip Hammond, said that triggering Brexit was “a pivotal moment for Britain,” but denied the country was taking a leap in the dark.

“We all have the same agenda. We are all seeking to get the best possible deal for Britain,” he told the BBC.

Hammond said he was optimistic of forging “a relationship that will strengthen the U.K. and will strengthen the European Union as well.”

Gus O’Donnell, the U.K.’s former top civil servant, was less certain.

“We are in a plane being flown by members of the EU and we’re about to jump out and we’ve got a parachute that was designed by the people flying the plane and they designed it in a way to deter anybody else jumping out,” he said.