Brexit ( a portmanteau of “British exit”) was the withdrawal of the United Kingdom (UK) from the European Union (EU) and the European Atomic Energy Community (EAEC or Euratom) at the end of 31 January 2020 CET. To date, the UK is the first and only country formally to leave the EU, after 47 years of membership within the bloc, after having first joined its predecessor, the European Communities (EC), on 1 January 1973. It continued to participate in the European Union Customs Union and European Single Market during a transition period that ended on 31 December 2020 at 23:00 GMT (00:00 CET). The European Union and its institutions have developed gradually since their establishment, including 47 years of British membership, and grew to be of significant importance to the UK. Throughout that time Eurosceptic groups had existed, opposing aspects of the Union and its predecessors. The public had previously approved the membership of the EC in a 1975 referendum, but no further referendums were held as the project grew and became “ever-closer” in the subsequent Maastricht and Lisbon treaties. Facing pressure from Eurosceptic groups, Prime Minister David Cameron’s pro-Europe government held a referendum in 2016 on whether to leave the EU, which passed by 51.9%. This led to his resignation, replacement by Theresa May, and four years of negotiations with the EU on the terms of departure and future relations. This process was politically challenging within the UK, with one deal rejected by the British parliament, general elections held in 2017 and 2019, and two new Prime Ministers in that time, both Conservative. Under Boris Johnson’s government, the UK left the EU on 31 January 2020 CET; trade deal negotiations continued to within days of the scheduled end of the transition period on 31 December 2020 CET. The effects of Brexit will be determined by the EU–UK Trade and Cooperation Agreement which was agreed on 24 December 2020 and ratified by the UK Parliament on 30 December 2020 and was “provisionsly” applied by the EU from the 31 December 2020. The broad consensus among economists is that Brexit will likely harm the UK’s economy and reduce its real per capita income in the long term, and that the referendum itself damaged the economy. Brexit is likely to reduce immigration from European Economic Area (EEA) countries to the UK, and poses challenges for British higher education, academic research and security; the Turing scheme was announced as a new global student exchange programme in early 2021 to combat this. Following Brexit, EU law and the EU Court of Justice no longer have supremacy over British laws or its Supreme Court. The European Union (Withdrawal) Act 2018 retains relevant EU law as domestic law, which the UK could then amend or repeal. Full HD.