What is Brexit?
Brexit – British exit – refers to the UK leaving the EU.

A public vote (known as a referendum) was held in June 2016, when 17.4 million people opted for Brexit. This gave the Leave side 52%, compared with 48% for Remain. The UK stopped being a member of the European Union (EU) after 23:00 GMT on 31 January 2020.

What is the European Union?
The EU is an economic and political union involving 28 European countries. It allows free trade, which means goods can move between member countries without any checks or extra charges. The EU also allows free movement of people, to live and work in whichever country they choose.
The UK joined in 1973 (when it was known as the European Economic Community) and it will be the first member state to withdraw.

Aside from trade, many other aspects of the future UK-EU relationship will also need to be decided. For example:

Law enforcement, data sharing, and security
Aviation standards and safety
Access to fishing waters
Supplies of electricity and gas
Licensing and regulation of medicines

Prime Minister Boris Johnson insists the transition period will not be extended, but the European Commission has warned that the timetable will be extremely challenging.