The Irish backstop (formally the Northern Ireland Protocol) is an annex to a draft Brexit withdrawal agreement drawn up by the May Government and the European Commission in December 2017 and completed in November 2018, which aimed to avoid an apparent border (with customs controls) between the Republic of Ireland and Northern Ireland after Brexit. They feared that the backstop would be used to permanently lure the UK into the EU customs union and prevent the country from concluding its own trade deals. In order to avoid a border between Northern Ireland and the rest of the United Kingdom, Article 6 of the Northern Ireland Protocol proposes that the United Kingdom and EU customs officers act as one from the end of the transition period (December 31, 2020) until the parties agree on a satisfactory alternative for both parties. [33] The single customs territory between the UK and the EU does not apply to fish products: for example, fish transported from Britain to Northern Ireland would be subject to EU tariffs in the absence of a separate fishing agreement. [34] Since this article was originally published in October 2018, the political situation around the backstop has changed. This is a summary of the main developments: according to the draft withdrawal agreement, the UK would enter a „transition period“ after Brexit (currently 31 October 2019). Under the new agreement, Northern Ireland will remain in the EU customs union for four years and will continue to trade with Ireland, as is currently the case. Then they can decide what to do. However, it is likely that there will be pest controls, inspections and tests for goods travelling between Ireland and Northern Ireland and Great Britain. This will have important implications for the economies of Northern Ireland, Ireland and the United Kingdom, as it will impose administrative and other burdens on businesses with little or no prior knowledge or expertise in these processes. Prime Minister Boris Johnson says he is determined to „get rid“ of the backstop, calling it „anti-democratic.“ In practice, this meant that the UK could not unilaterally leave the backstop in a scenario where a deadlock had been reached between the UK and the EU, not because of a proven failure of either side, but simply because of „intractable differences“.

The Leavers do not want an Irish backstop because they keep the UK in the customs union (free movement of goods and services with the EU) without having a say in how the bloc works. Former Prime Minister Theresa May negotiated a single backstop from Northern Ireland. However, the DUP rejected the agreement because it would create customs controls between Northern Ireland and the rest of the UK. Then came a British backstop that provoked a revolt among Conservative MPs, fearing that Britain would be caught in the EU`s embrace. Both the UK and the EU agreed that opening the border and respecting the terms of the Good Friday agreement were essential in negotiations on a post-Brexit deal.