The withdrawal agreement, in Part Four,[13] provided for a transition or implementation period[14] until 00:00 Central European Time on 1 January 2021 (11p.m.

[23][24] On the Irish border question, the Irish backstop was appended to the agreement setting a fall-back position if effective alternative arrangements failed to be agreed to avoid a hard border before the end of the transition period, with the UK shadowing the EU's Common external tariff and Northern Ireland keeping in aspects of the Single Market.

The withdrawal agreement also includes provisions for the UK to leave the Convention Defining the Statute of the European Schools, with the UK bound by the Convention and the accompanying regulations on Accredited European Schools until the end of the last academic year of the transition period, i.e. the end of the spring semester of 2020–2021.

Additionally, it states that by the end of the transition period, the UK shall be denied access to "any network, any information system and any database established on the basis of Union law" (Art.

The Agreement defines and provides the personal scope of citizens, family members, frontier workers, host states, and nationals.

Persons with valid documentation[clarification needed] would not require entry and exit visas or equal formalities and would be permitted to leave or enter the host state without complications (Art.

In case the host State demands "family members who join the Union citizen or United Kingdom national after the end of the transition period to have an entry visa", the host State is required to grant necessary visas through an accelerated process in appropriate facilities free of charge (Art.

The processes that start before the end of the transition period "shall be treated as an intra-Union movement regarding importation and exportation licensing requirements in Union law".

By way of derogation from previous Articles, the Title permits access to information systems that are necessary for the application or processing of the VAT (Art.

The fourth covers 'good governance in the area of taxation, environmental protection, labour and social standards, state aid, competition, and state-owned undertakings'.

The Protocol included a safety-net provision to handle the circumstances where satisfactory alternative arrangements remain to come into operation at the end of the transition period.

[29][30] Another difference was a unilateral exit mechanism for the Northern Ireland Assembly which has a vote every four years on whether to continue with these arrangements, for which a simple majority is required.

[31] A continuity with the backstop was providing for the application of EU-law in the area of goods and electricity and a role for the European Court of Justice with regards to procedures in case of non-compliance as well as the possibility and requirement for UK courts to ask for preliminary rulings on the application of EU law and related parts of the protocol.

According to Sam Lowe, trade fellow at the Centre for European Reform, the change excludes labour standards from dispute settlement mechanisms.

The advice given was that:[37] Immediately following announcement of a revised withdrawal agreement on 17 October 2019, Labour, the Liberal Democrats, and DUP said that they could not support the new deal.

[46][12] On 20 December 2019, following the Conservative victory in the 2019 United Kingdom general election, the House of Commons passed the second reading of the Withdrawal Agreement Bill by a margin of 358–234.

[52] "The UK launched its [registration] system for EU citizens last March [2020], with more than 3.3 million people granted pre-settled or settled status to remain in the country after Brexit", the Committee was told.

[53] On 6 September 2020, the Financial Times reported that the British government planned to draw up new legislation that would bypass the withdrawal agreement's Northern Ireland Protocol.

[54][55] The new law would give ministers the power to define what state aid needs to be reported to the EU, and define what products that at risk of being brought into Ireland from Northern Ireland (the withdrawal agreement states that in the absence of a mutual agreement, all products should be considered at risk).

[57] Ursula von der Leyen warned Johnson not to break international law, saying that the UK's implementation of the withdrawal agreement was a "prerequisite for any future partnership".

[59] On 1 October 2020, the European Commission sent a letter of formal notice to the British government as the first step in an infringement procedure, as the UK's Internal Market Bill would be "in full contradiction" to the Northern Ireland Protocol if adopted as-is.

[62] The EU objected to this and threatened to resort to legal action over what it said was the second time the UK had sought to breach international law in relation to the Northern Ireland Protocol.

On 4 March 2021, Irish Minister for Foreign Affairs Simon Coveney supported the Commission's threat of legal action if the UK "cannot be trusted" to implement the Protocol.

[64] The Windsor Framework, announced on 27 February 2023 and formally adopted by both parties on 24 March 2023, changes aspects of the Protocol's operation, particularly to ease custom checks on goods arriving from Great Britain.

[66] It gives the Northern Ireland administration and UK government a mechanism to object to, pause, and potentially disapply updated and amended EU laws, mainly concerning goods.