British Prime Minister Teresa May signed a letter to the leadership of the European Union about the beginning of the procedure for the UK's withdrawal from the EU, in accordance with Article 50 of the Lisbon Treaty.
The British permanent representative to the EU, Sir Tim Barrow, will deliver the letter to President of the European Council Donald Tusk at 12:30 BST on 29 March.
After that May will make a statement to MPs and call for support of the government's actions, which fulfills the will of voters who voted for Brexit in a referendum in June 2016.
The British government will negotiate with the EU on conditions for withdrawal and further coexistence. It is expected that the talks will last at least two years.