The United Kingdom voted to leave the European Union in June 2016. After much speculation over the future of the country and the bloc, British Prime Minister Theresa May signed a letter that formally kicks off the process for the country’s exit, Tuesday

The first requirement to put Brexit — the term for UK’s departure from the EU — into action is invoking Article 50 of the Lisbon Treaty. Under this, the British PM officially notified the union about its decision to leave the bloc.

Read: What Is Article 50, Which Will Trigger UK's Exit From The European Union?

The letter will be delivered by British envoy to the EU, Tim Barrow to European Council President Donald Tusk in Brussels at 11:30 a.m. GMT (7:30 a.m. EST). Copies of the letter also have to be sent to the remaining member states of the bloc.

May will also address the parliament after a meeting with the cabinet ministers early Wednesday. In the speech to the parliament, May will promise to “represent every person in the whole United Kingdom” during negotiations with the bloc, BBC reported.

“We are one great union of people and nations with a proud history and a bright future. And, now that the decision has been made to leave the EU, it is time to come together,” May is set to say.

“It is my fierce determination to get the right deal for every single person in this country,” May will say, BBC reported. “For, as we face the opportunities ahead of us on this momentous journey, our shared values, interests and ambitions can - and must - bring us together.”

The British PM also spoke with European leaders, including German Chancellor Angela Merkel, European Commission President Jean-Claude Juncker and Tusk, on Tuesday.

In the June referendum, 52 percent of the votes were for Brexit, compared to the 48 percent who wanted to stay in the union. While England and Wales voted to leave, Scotland and Northern Ireland voted overwhelmingly to stay in the EU.