The United Kingdom's decades-old ties to the European Union will begin to sever this afternoon when Britain's ambassador to the EU delivers a hand-signed letter from Prime Minister Theresa May to EU President Donald Tusk.
Around the same time back in London the PM will inform parliament that Article 50 has been invoked and the two-year deadline for the UK to leave the union will begin.
What exactly Brexit will mean for the citizens of Great Britain and the EU still remains unclear but nine months after voters expressed their desire to leave Europe the formal process will have commenced.
Ms May will tell lawmakers that it is her "fierce determination to get the right deal for every single person in this country," according to comments provided by her office.
"When I sit around the negotiating table in the months ahead, I will represent every person in the whole United Kingdom — young and old, rich and poor, city, town, country and all the villages and hamlets in between.
"We all want to live in a truly global Britain that gets out and builds relationships with old friends and new allies around the world."
But as well as navigating the UK's exit from Europe Ms May will also have to do her best to keep the United Kingdom united amid Scottish calls for a new referendum on independence.
Last year Scottish citizens cast their ballots overwhelmingly in favour of Britain remaining in the EU but with Brexit now about to take effect the Scottish National Party is calling on the PM to allow Scotland to decide whether it wants to be part of a United Kingdom outside Europe or an independent nation and EU member.
Within 48 hours of reading the letter, Mr Tusk will send the 27 other states draft negotiating guidelines. He will outline his views in Malta, where he will be attending a congress of centre-right leaders. Ambassadors of the 27 nations will then meet in Brussels to discuss Mr Tusk's draft.
Brexit will provide a test to the EU with the UK's exit leading to calls from within other member states to leave the union.
The EU leadership has stated a desire not to be too hard on the UK but a soft deal would likely embolden those in nations such as Italy and The Netherlands who want their countries to follow the UK out of Europe.