After an unprecedented vote on 4 December 2018, MEPs ruled that the UK government was not respecting Parliament because it refused to give Parliament full legal advice on the consequences of its proposed withdrawal terms.  The focus of the consultation was on the legal effect of the “backstop” agreement for Northern Ireland, the Republic of Ireland and the rest of the United Kingdom with regard to the CUSTOMS border between the EU and the United Kingdom and its impact on the Good Friday agreement that led to the end of the unrest in Northern Ireland, including whether , according to the proposals, the UK would be certain that it would be able to leave the EU in a practical sense. The UK has launched the formal process of withdrawal negotiations by formally announcing the European Council`s intention to leave the EU. Members who also rejected amendments to the House of Lords were not passed. This triggered Article 50 of the Treaty on the European Union, which defines the procedure for the withdrawal of an EU member state, thus opening a two-year countdown to withdrawal. On January 21, 2020, the House of Lords passed the law after passing five amendments. However, these amendments were overturned by the House of Commons the next day.   On 20 December 2019, after the Conservatives won the 2019 British general election, the House of Commons passed second reading of the withdrawal agreement with a 358-234 lead. Following the amendments proposed by the House of Lords and the ping-pong between the two houses, the bill was granted royal approval on 23 January 2020, allowing ratification on the British side.  The British Parliament approved the draft agreement by adopting 2020 implementing laws (The European Union Withdrawal Agreement (Withdrawal Agreement) 2020 Act. Following the signing of the agreement, the UK Government adopted and tabled the UK`s ratification instrument on 29 January 2020.  The agreement was ratified by the Council of the European Union on 30 January 2020, after approval by the European Parliament on 29 January 2020.
The UK`s withdrawal from the EU came into force on 31 January 2020 at 11 .m GMT, when the withdrawal agreement came into force in accordance with Article 185. On January 22, 2020, the law was passed by the House of Lords without further amendment. The next day she obtained royal approval.   Immediately after the announcement of a revised withdrawal agreement on October 17, 2019, Labour, the Liberal Democrats and the DUP declared that they could not support the new agreement.  The agreement also provides for a transitional period that will last until 31 December 2020 and may be extended by mutual agreement.