Renewed tensions between the United Kingdom and the European Union over the implementation of customs controls in Northern Ireland underscore the underlying problems that the Brexit deal failed to solve. While a short-term compromise between London and Brussels is possible, the Northern Ireland question will continue to create disputes between the European Union and the United Kingdom, while opening the door to sporadic episodes of violence in the area. On Feb. 3, U.K. Cabinet Office Minister Michael Gove asked the European Union to delay the implementation of full customs controls on the movement of goods between Great Britain and Northern Ireland until 2023 and to expand waivers on some products. 

• In late 2019, the European Union and the United Kingdom signed a Withdrawal Agreement (WA), which allowed the United Kingdom to exit the European Union in January 2020. In December of 2020, the United Kingdom also exited the European Union’s single market and customs union. The parties signed a Free Trade Agreement that entered into force on Jan. 1, 2021.
• The WA includes a so-called Northern Ireland protocol in which London and Brussels agreed to keep Northern Ireland in the EU single market and to perform customs controls on goods moving between Northern Ireland and Great Britain at the Irish Sea. This was necessary to keep the land border between Northern Ireland and the Republic of Ireland open, in line with the 1998 Good Friday Agreement.
• According to the Northern Ireland protocol, the customs controls would be applied progressively to allow ports and traders in Northern Ireland and Great Britain to adapt to the new situation. 
• In the early weeks of 2021, there were reports about isolated shortages of some food products in Northern Irish supermarkets, which was mostly due to the new bureaucracy created by the WA. 

The European Union wants to prevent Northern Ireland from becoming the weak spot of its customs union, while the United Kingdom wants to prevent Northern Ireland from threatening the unity of its internal market. These conflicting interests will continue to threaten the continuity of the existing Brexit economic and political deals. While the European Union and the United Kingdom have signed a free trade agreement, customs checks must still take place in order to ensure that the deal is applied correctly. The United Kingdom only reluctantly accepts the Northern Ireland protocol because it fragments its internal market by keeping Northern Ireland under a separate customs agreement. London also wants to prevent Northern Ireland from becoming a political and possible security problem at a time when it is dealing with the dual health and economic crises caused by the COVID-19 pandemic, as well as a renewed independence push in Scotland. As a result, London will constantly push for a softer implementation of the protocol, and may threaten to suspend its implementation as a pressure tactic in its negotiations with the European Union. For its part, the European Union will resist any calls to scrap the Northern Ireland protocol because it wants to protect the integrity of its customs union. Brussels wants to prevent Northern Ireland from becoming a point for goods entering the bloc illegally.

• On Feb. 3, U.K. Prime Minister Boris Johnson said “we will do everything we need to do” to “ensure there is no barrier down the Irish Sea." In September of 2020, the U.K. government also threatened to ignore the Northern Ireland protocol, arguing that the measures would fragment the United Kingdom’s internal market. 
• On Feb. 2, the Republic of Ireland’s Foreign Affairs Minister Simon Coveney admitted there were problems with the Northern Ireland protocol, but said calls to abolish it were “completely unrealistic” and “not going to happen.”
• On Jan. 29, the European Union briefly suggested that a land border control between Northern Ireland and the Republic of Ireland may be needed in order to prevent COVID-19 vaccines from leaving the European Union. Brussels backtracked from this suggestion a few hours later amid concerns voiced by EU countries and the United Kingdom about how such a decision would impact the WA.  
• In a Feb. 3 meeting between EU and U.K. officials to discuss current tensions, the European Union called for the “rigorous implementation” of the Northern Ireland protocol.
• According to the existing agreement, customs controls will not be applied to specific goods (such as pharmaceuticals and some food products) until April 1. A compromise is possible if the European Union accepts to extend this deadline, but the underlying problems connected to the WA will still create problems between London and Brussels. 

Opposition to the U.K.-EU Withdrawal Agreement in Northern Ireland will largely remain political. But while paramilitary forces in the region are much weaker than they were in the past, isolated episodes of violence and sabotage against customs workers and infrastructure cannot be ruled out. The Democratic Unionist Party (DUP), the largest unionist party in Northern Ireland, has repeatedly asked London to scrap the Northern Irish protocol in the WA. Unionist parties oppose the Northern Ireland protocol because it gives the region a separate status from the rest of the United Kingdom and creates obstacles to trade. Sinn Fein, the main republican party in Northern Ireland, also believes the problems related to the Northern Ireland protocol must be addressed, but has criticized unionist calls to abolish the agreement. On Feb. 1, Northern Ireland announced the suspension of some border controls at the ports of Belfast and Larne over concerns about the safety of customs workers and denounced a rise in “sinister and menacing behavior” in recent weeks. 

• In recent days, graffiti has appeared near Northern Irish ports warning that customs officials are “targets.” The Northern Irish police said it would increase patrols at ports.
• Northern Ireland’s first minister Arlene Foster of the DUP has criticized the threats against customs staff but insisted the Northern Irish protocol be abolished. 
• Deputy first minister Michelle O’Neill of Sinn Fein has accused the DUP of reckless behavior, saying that it and other unionist parties were trying to cause “tension and fear” in the country.  
• The Republic of Ireland’s Prime Minister Micheal Martin condemned “the intimidatory tactics against workers, who should of course be allowed to go about their daily work.”
• While most Northern Irish republican and unionist paramilitary forces disbanded after the Good Friday Agreement, some small groups remain active and have performed small attacks, intimidation campaigns and acts of sabotage in recent years. Criminal groups that benefit from smuggling and other illegal activities across the Irish Sea could also be interested in undermining the WAt. As a result, small-scale acts of violence and sabotage against customs staff and infrastructure are possible.