section_path: Opt-outs/Ireland and the United Kingdom
section_name: Ireland and the United Kingdom
paragraph_text: Ireland and the United Kingdom
  
  When EU states were negotiating subsuming the Schengen Agreement into the EU by the Treaty of Amsterdam, Ireland and the United Kingdom were the only member states that had not signed the Agreement. The UK did not want to join and Ireland wished to maintain its Common Travel Area with the United Kingdom and associated islands, an arrangement that would be incompatible with Schengen membership while the UK remained out. As a result, both negotiated an opt-out from the part of the treaty which was to incorporate the Schengen rules (or acquis) into EU Law when it came into effect on 1 May 1999. Under the relevant protocol, either may request to participate in aspects of the Schengen acquis but this is subject to the approval of the Schengen states.
  
  On 31 January 2020, the United Kingdom withdrew from the European Union and the protocol ceased to apply to it. Ireland will continue to operate the Common Travel Area and not join the Schengen Area for the foreseeable future, because it wants to keep open its land border with the UK.
  
  In 1999, the UK formally requested participation in certain provisions of the Schengen acquis – Title III relating to Police Security and Judicial Cooperation, and this request was approved by the Council of the European Union on 29 May 2000. The United Kingdom's formal participation in the previously approved areas of cooperation was put into effect by a 2004 Council decision that came into effect on 1 January 2005. Although the United Kingdom was not part of the Schengen passport-free area, it still used the Schengen Information System, a governmental database used by European countries to store and disseminate information on individuals and property. This allowed the UK to exchange information with countries that are a part of the Schengen agreement, often for the sake of liaising over law enforcement. In 2020, the UK declared its intent to withdraw from these arrangements at the end of its transition period, and did so on 31 December 2020.
  
  In contrast, while Ireland initially submitted a request to participate in the Schengen acquis in 2002, which was approved by the Council of the European Union, that decision took nearly eighteen years to be put into effect. In February 2010 the Irish Minister for Justice, in response to a parliamentary question, said that: "The measures which will enable Ireland to meet its Schengen requirements are currently being progressed". Ireland joined the law enforcement aspect of SIS II on 1 January 2021 with plans to have "full operational capacity" two months later. Ireland is connected to the Schengen Information System (SIS II) and systematically checks all identity documents on SIS II at airports and designated ports of entry (including flights from the UK).