<P> A view has been expressed by some legal thinkers, political actors and journalists that the triggering of Article 50 was on a legal basis technically flawed, with legislation failing to explicitly seek a decision of the UK Parliament . However, on 1st February 2017 four hundred and ninety eight MP's, (the vast majority) voted in favour to give the British Prime Minister the power to trigger Article 50 . </P> <P> The issue of whether the UK's invocation of Article 50 can be revoked is unclear . The EU Commission and the European Parliament Brexit committee have said that reversal has to be agreed by the other EU countries while its author Lord Kerr has asserted that the Article 50 notification is reversible unilaterally . </P> <P> Both parties to the withdrawal negotiation are bound by Article 50 (3), which states explicitly that the EU treaties will cease to apply "from the date of entry into force of the withdrawal agreement or, failing that, two years after" the withdrawal notification unless the EU Council and UK agree to extend the two - year period . The European Union's Directives for the negotiation of an agreement notes that "The Agreement should set a withdrawal date which is at the latest 30 March 2019 at 00: 00 (Brussels time),"--i.e. Central European Time--"unless the European Council, in agreement with the United Kingdom, unanimously decides to extend this period in accordance with Article 50 (3) of the Treaty on European Union ." The UK government does not mention a date, but states in the European Union (Withdrawal) Bill that "' exit day' means such day as a Minister of the Crown may by regulations appoint". In the United Kingdom, when a day is appointed for legislation to come into force, this normally means at the beginning of that day . </P> <P> The British and EU negotiators agreed that initial negotiations, relating especially to residency rights, would commence in June 2017 (immediately after the French presidential and parliamentary elections), and full negotiations, relating especially to trading agreements, could commence in October 2017 (immediately after the German federal election, 2017). The first day of talks was 19 June . </P>

When did the uk leave the european union
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