British citizens voted Thursday to leave the European Union. There are steps outlined for members wishing to withdraw from the bloc, but no country has ever left, so the process is uncertain. First, Britain tells the European Council it wants to exit. The basic steps of the withdrawal process are described in Article 50 of the Treaty on European Union. It officially begins when the European Council is notified. One government leader (such as a prime minister, president or chancellor) from each of the 28 member countries is in the European Council. The group also includes its own president.

Article 50 does not say when this notification should take place, and it is unclear how soon Britain will start the exiting process.