The UK's withdrawal from the EU and the adoption and implementation of the Protocol on Ireland/Northern Ireland has seen the production of numerous documents, many of which are in the public domain. Navigating through relevant websites and picking out the most important documents can, however, be challenging. This page identifies key documents. 

The presentation of the key documents is divided into three phases:

• Negotiating Withdrawal and the Protocol
• Transition and Preparing for Implementation of the Protocol
• Implementing the Protocol 

The latter section will be regularly updated as new key texts are published. 

Negotiating Withdrawal and the Protocol

The UK voted to leave the EU in a referendum held on 23 June 2016. In the aftermath of the vote, Northern Ireland's First Minister and deputy First Minister on 10 August 2016 wrote to the newly appointed UK Prime Minister Theresa May to set out an "initial assessment" of issues "of particular significance" to Northern Ireland. They  stated their shared objective that the land border "will not become an impediment to the movement of people, goods and services" on the island of Ireland. The Prime Minister's response on 14 October 2016 described the "future of the border with Ireland" as an "important priority for the UK" and stated the government's "wish to see the continuance of the free movement of people and goods" across it. 

On 17 January 2017 Prime Minister May set out the UK's 12 negotiating objectives for exiting the EU in a speech at Lancaster House. Several weeks later, Prime Minister May sent a letter to European Council President Donald Tusk giving formal notification of the UK's intention to leave the EU thereby triggering the withdrawal process laid down in Article 50 of the Treaty on the European Union (TEU).

Following UK notification, EU leaders in the European Council adopted Guidelines Following the United Kingdom's Notification under Article 50 TEU on 29 April 2017. UK-EU negotiations on the terms of withdrawal began in June 2017. According to an agreed timetable, negotiations on future UK-EU relations would not start until 'sufficient progress' had been made on withdrawal issues, namely: citizens rights, the financial settlement and arrangements for the unique circumstance on the island of Ireland. Early on in negotiations, the UK government published Northern Ireland and Ireland: position paper which set out UK objectives in some more detail. On 22 September 2017, the UK Prime Minister set out UK vision for a "deep and special partnership" between the UK and EU after Brexit in a speech at Florence.  

In December 2017, UK and EU negotiators produced a Joint Report on progress in the negotiations. This contains key commitments concerning the Northern Ireland dimension to withdrawal (see especially paragraphs 49 and 50). The agreements and commitments in the Joint Report were translated into a draft Withdrawal Agreement by the European Commission in early 2018 and shared with the UK. A further draft indicating levels of agreement between the UK and the EU was published in March 2018. This concerned the terms of the UK's withdrawal. As for the post-withdrawal relationship between the UK and the EU, the European Council adopted Guidelines on 23 March 2018.

A further report on the state of the withdrawal negotiations - this time in the form of a joint statement - was issued on 19 June 2018. It identified areas where agreement was still outstanding. It was not until November 2018 that negotiations were concluded and both the UK and the EU issued "explainers" and/or slides of what had been agreed. The UK Prime Minister, Theresa May, was unable to secure parliamentary support for what had been agreed with the EU. She resigned and was replaced by Boris Johnson who immediately sought to re-open what had been agreed, particularly regarding the so-called 'backstop' Protocol on Ireland/Northern Ireland. He set out the new UK government's position in a letter to the President of the European Council, Donald Tusk, on 19 August 2019.

The Protocol was then revised, and agreement reached for a second time on the terms of the UK's withdrawal from the EU.  Again, the UK and the EU issued explainers. The Withdrawal Agreement was then approved by the UK Parliament and the European Parliament and signed. The EU published its official version of the Withdrawal Agreement - including the Protocol - on 31 January 2020. UK membership of the EU ceased at 2300 UK time - midnight in Brussels. 

Transition and Preparing for Implementation of the Protocol

Following its formal withdrawal from the EU on 31 January 2020 the UK entered into a 'Transition' period until 31 December 2020. During these 11 months EU law continued to apply in the UK. Transition was due to be used to prepare for the full implementation of the Protocol on Ireland/Northern Ireland. Both the UK and the EU published various key documents concerning implementation. The UK government also announced that it would not be availing of the opportunity to extend the Transition period

A first key document relating to the Protocol was a Technical Note on the implementation of the Protocol published by the European Commission on 20 April 2020.

This was followed by Command Paper setting out The UK's Approach to the Northern Ireland Protocol published by the UK Government on 20 May 2020. 

On 10 December 2020, following 'in principle' agreement with the EU on a number of outstanding issues concerning the implementation of the Protocol, the UK government published a second Command Paper on The Northern Ireland Protocol setting out its perspective on what had been agreed. A week later the EU-UK Joint Committee adopted the related Decisions. 

Implementating the Protocol

Since the end of the Transition Period on 1 January 2021 and the entry into force of the Protocol on Ireland/Northern Ireland, the UK and EU have produced a series of key documents regarding its implementation. 

On 9 June 2021 the European Commission published a table comparing the effects of the EU-Switzerland Veterinary Agreement (alignment) and EU-New Zealand Veterinary Agreement (equivalence) to demonstrate their implications for EU import requirements, authorisations and prohibitions for animal products: comparison between different categories of third countries. The purpose of the exercise was to demonstrate how a EU-UK veterinary agreement could reduce checks and controls on the movement of goods between Great Britain and Northern Ireland

On 21 July 2021 the UK Government published a Command Paper entitled Northern Ireland Protocol: the way forward which outlined a series of UK proposals for amending the Protocol and the requirements for its implementation.

On 27 July 2021 the European Commission published a revised paper containing examples of flexibilities it had identified to facilitate the full implementation of the Protocol and specific 'non-papers' on the implementation of the Protocol in respect of medicines and SPS measures.

On 13 October 2021 the European Commission published four 'non-papers' setting out proposals for the implementation of the Protocol relating to customs, SPS, medicines and Northern Ireland stakeholder engagement. Accompanying the 'non-papers' the Commission published factsheets on: the benefits of the Protocol; updated examples of flexibilities and concrete examples of the potential impact of the EU proposals.

On 13 June 2022 the UK Government publish its Northern Ireland Protocol Bill which, if passed, would disapply elements of the Protocol in UK law and give UK Ministers sweeping powers to make law in areas previously covered by the Protocol. Explanatory Notes, an explainer and the UK Government's legal advice and justification for the new Bill are also published. 

On 15 June 2022 the European Commission publish position papers on customs and SPS issues setting out more details regarding proposals made in its 'non-papers' in October 2021.