Brexit background

In a national referendum on 23 June 2016, a majority of 51.9% of British citizens voted to withdraw from the European Union ("Brexit). An immediate second Brexit referendum was demanded by an online petition but swiftly ruled out by UK government. (2)

For more background: Wikipedia

Brexit timing considerations

As the next step, the UK government has to notify the European Council formally of the UK’s intention to withdraw from the EU, as required by Article 50 of the Treaty on the European Union. (1)

It is uncertain if and when this notification will be realized. The UK's incumbent Prime Minister David Cameron stated that the withdrawal negotiations - thus the formal notification - will be the next Prime Minister's task. His successor will be determined at the UK Conservative Party leadership elections in October 2016. (3)

External sources

1. The Treaty on European Union, Article 50 - Wikisource
2. David Cameron rules out possibility of second EU referendum - The Independent, 27 June 2016
3. EU says 'no need' for UK to send formal letter - The Independent, 26 June 2016 Tagesschau.de, 10 June 2016