On 29 March 2017 the British government gave formal notice of the UK's intention to leave the European Union in a letter to the European Council. The UK is thus expected to withdraw from the EU at the end of March 2019, following the two-year period of negotiation provided under Article 50 of the Treaty on European Union. However, this may be extended with the consent of the UK and all EU member states.
The withdrawal negotiations between the UK and the EU started on 19 June 2017. On 8 December 2017 the UK and the EU released a joint report, stating that both parties have reached agreement in principle on the main terms of the UK’s withdrawal from the EU. More information on what the deal entails with regard to citizens’ rights can be found below.
The negotiations between the UK and the EU on the question of a transition phase and the future relations will continue in 2018.
Only once the UK's withdrawal from the EU comes into effect will the treaties governing the UK's relations with the EU cease to apply. The same goes for the agreements that the EU has negotiated with third countries, including the Switzerland–EU bilateral agreements.