BACKGROUND Brexit timetable: What happens next in Britain's exit from the EU?

Brussels (dpa) - In June last year, Britain voted in a referendum to leave the European Union. On Wednesday, Prime Minister Theresa May officially notified the European Council of Britain‘s EU departure, by triggering Article 50 of the Treaty on the European Union.Now that the two-year countdown to Brexit has been launched, the ball is in the EU‘s court. EU MANDATE: With Britain‘s intention to leave becoming official, the rest of the EU must spring into action. The leaders of the 27 other member states will come together at a special summit on April 29 in Brussels. They will then produce guidelines for their side of the negotiations, which will determine the future of Britain‘s relationship with the EU. NEGOTIATIONS: The EU‘s chief Brexit negotiator, Michel Barnier, and his team of around 20 experts expect the actual negotiations for the terms of the divorce and any transitional arrangements to last 18 months, meaning they are likely to conclude around October 2018. TWO-YEAR DEADLINE: Britain and the EU have two years from the point at which Article 50 is officially triggered to thrash out a deal. If May‘s plan for formalizing Britain‘s departure stays on track, the country‘s EU membership will automatically expire by March 29, 2019. RATIFICATION: On the EU side, the deal must be put to the European Parliament for approval before being accepted by the European Council - without Britain‘s involvement. On the British side, Theresa May plans to present the deal to the British parliament before giving the final go-ahead for ratification.