The Prime Minister will formally notify Brussels of the UK's exit in nine days time, beginning the two-year countdown until Brexit is complete.
It will also kick off the timetable for formal talks on Britain's exit, with the 27 remaining EU member states set to outline their negotiating position later next week.
Britain's ambassador to the EU Sir Tim Barrow this morning informed the office of European Council President Donald Tusk of the UK’s intention to invoke Article 50 next Wednesday.
Brexit Secretary David Davis said: "Last June, the people of the UK made the historic decision to leave the EU.
"Next Wednesday, the Government will deliver on that decision and formally start the process by triggering Article 50.
"We are on the threshold of the most important negotiation for this country for a generation.
I wonder if this will become a domino effect. I am sure thre will be other countries thinking the same.