Between 2017 and 2019, representatives of the United Kingdom and the European Union negotiated the terms for Brexit, the planned withdrawal of the UK from the EU. These negotiations arose following the decision of the Parliament of the United Kingdom to invoke Article 50 of the Treaty on European Union, following the UK's EU membership referendum on 23 June 2016. In March and April 2019, Prime Minister of the United Kingdom Theresa May and European Union leaders agreed to move the date of the UK's departure to 31 October 2019.