May sent the letter to European Council President Donald Tusk Wednesday to trigger Article 50 of the Lisbon Treaty. A two-year process to take the country out of the EU will now begin.
The prime minister called it “the moment for the country to come together” in an address to members of parliament.
Once Article 50 is triggered, an eight-week process to set guidelines will take place after the EU issues a formal response. Actual negotiations are not expected until June at the earliest. May hopes to negotiate a deal that both satisfies eurosceptics in the U.K. and keeps the country on good terms with the 27 countries still in the EU.
“It is my fierce determination to get the right deal for every single person in this country,” May said in her address, according to BBC. “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.”