Brexit negotiations in 2018 took place between the United Kingdom and the European Union for the withdrawal of the United Kingdom from the European Union following the United Kingdom European Union membership referendum on 23 June 2016. The negotiating period began on 29 March 2017 when the United Kingdom served the withdrawal notice under Article 50 of the Treaty on European Union. The period for negotiation stated in Article 50 is two years from notification, unless an extension is agreed. In March 2019, British prime minister Theresa May and European leaders negotiated a two-week delay for the Parliament of the United Kingdom to agree on the government's Brexit treaty, moving the date from 29 March 2019 to 12 April 2019. Negotiations between the United Kingdom and the European Union regarding Brexit began in June 2017, with the following negotiations taking place during 2018.