Whether the deal that broke the deadlock in The Brexit talks has been legally binding has been the subject of much discussion since the deal was announced on 8 December. From a technical point of view, the answer depends on the question from the point of view of law or policy. But more broadly, it is a classic example of a case where law and politics are closely linked. The withdrawal agreement setting the terms of Brexit will be an international treaty between the UK and the EU, in accordance with the wording of Article 50 of the Treaty on European Union, which refers to an „agreement“. The treaties are legally binding under the Vienna Convention on Treaty Law. The British Parliament approved the draft agreement by adopting on 23 January 2020 the implementing laws (the 2020 Withdrawal Agreement Act) of the European Union (withdrawal agreement). 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 15 January 2019, the House of Commons voted with 230 votes against the Brexit withdrawal agreement the largest vote against the British government in history.  The government may survived a vote of confidence the next day.  On March 12, 2019, the House of Commons voted 149 votes against the agreement, the fourth-biggest defeat of the government in the history of the House of Commons.  A third vote on the Brexit withdrawal agreement, widely expected on 19 March 2019, was rejected by the House of Commons spokesman on 18 March 2019, on the basis of a parliamentary convention of 2 April 1604, which prevented British governments from forcing the House of Commons to vote several times on a subject already voted on by the House of Commons.    An abbreviated version of the withdrawal agreement, in which the annex political statement had been withdrawn, consisted of the test of „substantial amendments,“ so that a third vote was held on 29 March 2019, but was rejected by 58 votes.  The agreement defines goods, services and related processes. Any provision of goods or services legally put on the market before leaving the EU may be made available to consumers in the UK or in the EU Member States (Article 40-41). The withdrawal agreement provided for an extension of the transition period to avoid the „non-deal“ of Brexit if no agreement between the EU and the UK could be reached by 31 December 2020. Such an extension should have been requested until July 2020. Following a statement by Prime Minister Boris Johnson that he would not use this option and that 11 months would be enough to reach a comprehensive agreement, the British government added a provision to the 2020 Law to prohibit a British minister who wants such an extension, and no extension was sought.
The Northern Ireland Protocol, known as the Irish Backstop, was an annex to the November 2018 draft agreement outlining provisions to avoid a hard border in Ireland after the UK`s withdrawal from the European Union. The protocol provided for a provision of the safety net to deal with the circumstances in which satisfactory alternative arrangements were to come into force at the end of the transition period. This project has been replaced by a new protocol that will be described as follows. The withdrawal agreement provides for a transitional period until 31 December 2020, during which time the UK will remain in the internal market, to ensure the smooth flow of trade until a long-term relationship is concluded. If no agreement is reached by then, the UK will leave the single market without a trade deal on 1 January 2021.