The UK prime minister said that there can be "no turning back" from Brexit as the Article 50 has been triggered.
"A few minutes ago in Brussels, the United Kingdom’s Permanent Representative to the EU handed a letter to the President of the European Council on my behalf, confirming the government’s decision to invoke Article 50 of the Treaty on European Union … This is an historic moment from which there can be no turning back. Britain is leaving the European Union."
"I want us to be a truly Global Britain – the best friend and neighbor to our European partners, but a country that reaches beyond the borders of Europe too. A country that goes out into the world to build relationships with old friends and new allies alike," May said in the House of Commons, as quoted by her office.
She stressed that the country was leaving EU institutions, not Europe itself.
"We will remain a close friend and ally. We will be a committed partner. We will play our part to ensure that Europe is able to project its values and defend itself from security threats. And we will do all that we can to help the European Union prosper and succeed," the prime minister said.
She said that she is aware of possible consequences of Britain's exit from the EU.
Britain will remain being a committed partner of the EU after Brexit, she said, adding that the UK will help Europe defend itself from threats.
"In the letter that has been delivered to President Tusk today… I have been clear that the deep and special partnership we seek is in the best interests of the United Kingdom and of the European Union too," May said.
Theresa May said that the UK devolved administrations will receive more powers after Brexit. She added that a White Paper on law changes will be published on Thursday.
"And it is the expectation of the government that the devolved administrations in Scotland, Wales and Northern Ireland will see a significant increase in their decision-making power as a result of this process."
"I choose to believe in Britain and that our best days lie ahead. And I do so because I am confident that we have the vision and the plan to use this moment to build a better Britain … I have set out a clear and ambitious plan for the negotiations ahead."
UK Permanent Representative to the European Union Tim Barrow gave a letter of official notification of the United Kingdom’s withdrawal from the bloc signed by UK Prime Minister Theresa May to Tusk earlier on Wednesday.
"We will pursue a bold and ambitious free trade agreement with the European Union that allows for the freest possible trade in goods and services between Britain and the EU’s member states; that gives British companies the maximum freedom to trade with and operate within European markets; and that lets European businesses do the same in Britain."
After the letter is received by the European Council, the two-year countdown on Brexit negotiations will begin.
According to the rules set out by the Article 50 of the Lisbon Treaty, the country which wishes to withdraw from the bloc has to do so two years after the official notification. Therefore, the United Kingdom should leave the European Union on March 29, 2019.
The European Union member states' permanent representatives are expected to gather on Friday to draft a detailed Brexit negotiations plan, which would be considered at the April 27 European Council meeting and the April 29 Special European Council on Article 50.
On June 23, 2016, the United Kingdom held a referendum to determine whether or not the country should leave the European Union. The majority of Britons supported the decision to leave the 28-nation bloc.