In general, thelaw of the European Union is valid in all of the twenty-sevenEuropean Unionmember states. However, occasionally member states negotiate certainopt-outs from legislation or treaties of the European Union, meaning they do not have to participate in certain policy areas. Currently, three states have such opt-outs:Denmark (two opt-outs),Ireland (two opt-outs) andPoland (one opt-out). TheUnited Kingdom hadfour opt-outs beforeleaving the Union.
This is distinct from theenhanced cooperation, a measure introduced in theTreaty of Amsterdam, whereby a minimum of nine member states are allowed to co-operate within thestructure of the European Union without involving other member states, after theEuropean Commission and aqualified majority have approved the measure. It is further distinct from theMechanism for Cooperation and Verification, whose lifting is conditional on the relevant member states meeting certain benchmarks, and temporary derogations from certain areas of cooperation (such as theSchengen Agreement and theeurozone) until the relevant member states satisfy the entry conditions.
| Country | Number of opt‑outs | Policy area | |||||
|---|---|---|---|---|---|---|---|
| Economic and Monetary Union (EMU) | Area of freedom, security and justice (AFSJ) | Security and Defence Policy (CSDP) | Social Chapter | ||||
| Eurozone | General AFSJ | Schengen Area | Charter of Fundamental Rights | ||||
| Current member state opt-outs (as of 2024) | |||||||
 Denmark (details) | 2 | Opt-out[a] | Opt-out | Intergovernmental | No opt-out | Former opt-out | No opt-out |
 Ireland | 2 | No opt-out | Opt-out (opt-in) | Opt-out (opt-in) | No opt-out | No opt-out | No opt-out |
 Poland | 1 | Derogation[b] | No opt-out | No opt-out | Opt-out[c] | No opt-out | No opt-out |
| Former member state opt-outs (as of date of withdrawal in 2020) | |||||||
 United Kingdom (details) | 4 | Opt-out | Opt-out (opt-in) | Opt-out (opt-in) | Opt-out[c] | No opt-out | Former opt-out |
| |||||||
As of 2024, three states have formal opt-outs from a total of four policy areas.
All member states other than Denmark have either adopted the euro or are legally bound to do so. TheMaastricht Treaty of 1992 includedprotocols on the UK[1] (a member state at the time) andDenmark giving them opt-outs with the right to decide if and when they would join the euro. Denmark subsequently notified the Council of the European Communities of their decision to opt-out of the euro, and this was included as part of the 1992Edinburgh Agreement, aDecision of Council, reached following the Maastricht Treaty's initial rejection in a1992 Danish referendum. The purpose of the agreement was to assist in its approval in asecond referendum, which it did. The Danish decision to opt-out was subsequently formalized in anamended protocol as part of theLisbon Treaty.
In 2000, the Danish electorate voted against joining the euro in areferendum by a margin of 53.2% to 46.8% on a turnout of 87.6%.
While the remaining states are all obliged to adopt the euro eventually by the terms of their accession treaties, since membership in theExchange Rate Mechanism is a prerequisite for euro adoption, and joining ERM is voluntary, these states can ultimately control the timing of their adoption of the euro by deliberately not satisfying the ERM requirement.
Denmark and Ireland have opt-outs from the area of freedom, security and justice in general, while Denmark and Ireland have opt-outs from the Schengen Agreement and Poland has an opt-out from the applicability of the Charter of Fundamental Rights.
The United Kingdom also had opt-outs from all of these policy areas prior to itswithdrawal from the European Union in 2020.
Ireland has a flexible opt-out from legislation adopted in thearea of freedom, security and justice, which includes all matters previously part of the pre-AmsterdamJustice and Home Affairs (JHA) pillar.[2] This allows it to opt-in or out of legislation and legislative initiatives on a case-by-case basis, which it usually does, except on matters related to the Schengenacquis.[3] The opt-out from the JHA policy area was originally obtained by Ireland and the United Kingdom in aprotocol to the Treaty of Amsterdam of 1997, and was retained by both in the Treaty of Lisbon.[4] A review published by the Irish government in 2025 concluded that "Ireland should continue to be covered by the terms of the Protocol" but that it should "take part in AFSJ measures to the maximum extent possible".[5]
In contrast, Denmark has a more rigid opt-out from the area of freedom, security and justice. While the Edinburgh Agreement of 1992 stipulated that "Denmark will participate fully in cooperation on Justice and Home Affairs",[6] the Treaty of Amsterdam of 1997 included aprotocol which exempted it, as a matter of EU law, from participating in these policy areas, which are instead conducted on an intergovernmental basis with Denmark. A number of parallel intergovernmental agreements have been concluded between the EU and Denmark to extend to it EU Regulations adopted under the area of freedom, security and justice, which Denmark can't participate in directly due to its opt-out. In the negotiations of the Lisbon Treaty, Denmark obtained an amendment to theprotocol to give it the option to convert its opt-out from the Area of freedom, security and justice (which had incorporated the former Justice and Home Affairs pillar) into a flexible opt-in modelled on the Irish and British opt-outs.[7] In areferendum on 3 December 2015, 53.1% rejected exercising this option.[8]
TheSchengen Agreement abolished border controls between European Community member states which acceded to it. When theTreaty of Amsterdam of 1997 incorporated it into theEU treaties, Ireland and the United Kingdom (a member state at the time) received opt-outs from implementing theSchengenacquis as they were the only EU member states that had not signed the agreement. However, theprotocol on the Schengen acquis specified that they could request to opt-in to participating in Schengen measures on a case-by-case basis if they desired, subject to unanimous approval of the other participating states.
Theprotocol on the Schengen acquis andprotocol on Denmark of the Treaty of Amsterdam stipulate thatDenmark, which had signed an accession protocol the Schengen Agreement, would continue to be bound by the provisions and would have the option to participate in future developments of the Schengen acquis, but would do so on an intergovernmental basis rather than under EU law for the provisions that fell under theJustice and Home Affairs pillar, from which Denmark obtained an opt-out. When a measure is adopted which builds upon the Schengen acquis, Denmark has six months to decide whether to implement it. If Denmark decides to implement the measure, it takes the force of an international agreement between Denmark and the Schengen states. However, the protocol stipulates that if Denmark chooses not to implement future developments of the Schengen acquis, the EU and its member states "will consider appropriate measures to be taken".[9] A failure by Denmark to implement a Schengen measure could result in it being excluded from the Schengen Area.[10] The Protocol on Denmark's general opt-out from the AFSJ stipulates that if Denmark exercises its option to convert its opt-out into a flexible opt-in, then it will be become bound by the Schengen acquis under EU law rather than on an intergovernmental basis.
Ireland submitted a request to participate in the Schengenacquis in 2002, which was approved by the Council of the European Union.[11] A Council decision in 2020 approved the implementation of the provisions on data protection andSchengen Information System to Ireland.[12]
Ireland joined the UK in adopting this opt-out to keep their border withNorthern Ireland open via theCommon Travel Area (CTA).[1][13][14] Prior to therenewal of the CTA in 2011, when the British government was proposing that passports be required for Irish citizens to enter the UK,[15] there were calls for Ireland to join the Schengen Area.[14] However, in response to a question on the issue,Bertie Ahern, the then-incumbentTaoiseach, stated: "On the question of whether this is the end of the common travel area and should we join Schengen, the answer is 'no'."[14][16]
Although Poland participates in thearea of freedom, security and justice, it secured — along with another then-member state the United Kingdom — aprotocol that clarified how theCharter of Fundamental Rights of the European Union, a part of the Treaty of Lisbon, would interact with national law in their countries limiting the extent that European courts would be able to rule on issues related to the Charter if they were brought to national courts.[17] Poland's then ruling party,Law and Justice, mainly noted concerns that the Charter might force Poland to grant homosexual couples the same kind of benefits that heterosexual couples enjoy.[18] TheEuropean Scrutiny Committee of theBritish House of Commons, including members of both theLabour Party and theConservative Party, cast doubts on the protocol's text, asserting that the clarification might not have been worded strongly and clearly enough to achieve the government's aims.[19][20][21]
After theCivic Platform won the2007 parliamentary election in Poland, it announced that it would not opt-out from the Charter, leaving the United Kingdom as the only state not to adopt it.[22] However,Donald Tusk, the new Prime Minister and leader of the Civic Platform, later qualified that pledge, stating he would consider the risks before abolishing the opt-out,[23] and on 23 November 2007, he announced that he would not eliminate the Charter opt-out after all (despite the fact that both his party and their coalition partner, thePolish People's Party, were in favour of eliminating it), stating that he wanted to honour the deals negotiated by the previous government and that he needed the support ofLaw and Justice to gain thetwo-thirds majority in theParliament of Poland required to approve ratification of theTreaty of Lisbon.[24] Shortly after the signature of the treaty, the PolishSejm passed a resolution that expressed its desire to be able to withdraw from the Protocol.[25] Tusk later clarified that he may sign up to the Charter after successful ratification of the Treaty of Lisbon has taken place.[26] However, after the treaty entered into force a spokesperson for thePolish President argued that the Charter already applied in Poland and thus it was not necessary to withdraw from the protocol. He also stated that the government was not actively attempting to withdraw from the protocol.[27]Polish Minister of Foreign AffairsRadosław Sikorski, of Civic Platform, argued that the protocol only narrowly modified the charter's application in Poland, and that formally renouncing the opt-out would require a treaty amendment that would need to be ratified by all EU member states.[28] In April 2012,Leszek Miller, leader of theDemocratic Left Alliance, stated that he would sign the charter if he comes to power.[29] According toAndrew Duff, BritishMember of the European Parliament, "A Polish constitutional mechanism has since been devised whereby Poland can decide to amend or to withdraw from the Protocol, and such a possibility remains under review."[30]
Several times an EU member state has faced domestic public opposition to the ratification of an EU treaty leading to its rejection in a referendum. To help address the concerns raised, the EU has offered to make a "legal guarantee" to the rejecting state. These guarantees did not purport to exempt the state from any treaty provisions, as an opt-out does. Instead they offered a clarification or interpretation of the provisions to allay fears of alternative interpretations.
As part of the 1992 Edinburgh Agreement, Denmark obtained a clarification on the nature ofcitizenship of the European Union which was proposed in the then yet-to-come-into-forceMaastricht Treaty.[31] The Agreement was in the form of a Decision of Council.[32] The part of the agreement, which only applied to Denmark, relating to citizenship was as follows:
The provisions of Part Two of the Treaty establishing the European Community relating to citizenship of the Union give nationals of the Member States additional rights and protection as specified in that Part. They do not in any way take the place of national citizenship. The question whether an individual possesses the nationality of a Member State will be settled solely by reference to the national law of the Member State concerned.
The guarantee to Denmark on citizenship was never incorporated into the treaties, but the substance of this statement was subsequently added to theAmsterdam Treaty and applies to all member states.Article 2 states that:
Citizenship of the Union shall complement and not replace national citizenship.
Following therejection of the Treaty of Lisbon by the Irish electorate in 2008, a number of guarantees (on security and defence, ethical issues and taxation) were given to the Irish in return for holding a second referendum. On thesecond attempt in 2009 the treaty was approved. Rather than repeat the ratification procedure, the guarantees were merely declarations with a promise to append them to the next treaty.[33][34]
The member states ultimately decided not to sign the protocol alongside theCroatian accession treaty, but rather as a single document. A draft protocol to this effect[35] was proposed by theEuropean Council and adopted by theEuropean Parliament in April 2012.[36] An Intergovernmental Conference followed on 16 May,[37] and the protocol was signed by all states of the European Union between that date and 13 June 2012.[38] The protocol was planned to take effect from 1 July 2013, provided that all member states had ratified the agreement by then,[39] but it only entered into force on 1 December 2014.[40]
During its membership of the European Union, the United Kingdom had five opt-outs from EU legislation (from the Economic and Monetary Union, the area of freedom, security and justice, the Schengen Agreement, the Charter of Fundamental Rights, and the Social Chapter), four of them remained in force whenit left the EU, the most of any member state.
In the United Kingdom, theLabour government ofTony Blair argued that the country should revoke its EMU opt-out and join the euro, contingent on approval in a referendum, iffive economic tests were met. However, the assessment of those tests in June 2003 concluded that not all were met.[41] The policy of the 2010s coalition government,elected in 2010, was against introducing the euro prior to the2015 general election.[42]
UnderProtocol 36 of theLisbon Treaty, the United Kingdom had the option to opt-out of all police and criminal justice legislation adopted prior to the treaty's entry into force which had not been subsequently amended. The decision to opt-out had to be made at least six months prior to the aforementioned measures coming under the jurisdiction of theEuropean Court of Justice on 1 December 2014. The UK informed theEuropean Council of their decision to exercise their opt-out in July 2013,[43] and as such, the aforementioned legislation ceased to apply to the UK as of 1 December 2014.[44][45] While the protocol only permitted the UK to either opt-out from all the legislation or none of it, they subsequently opted back into some measures.[46][47][48]
The UK formally requested to participate in certain provisions of the Schengenacquis – Title III relating to Police Security and Judicial Cooperation – in 1999, and this was approved by theCouncil of the European Union on 29 May 2000.[49] The implementation of some of the previously approved areas of cooperation to the United Kingdom was approved in a 2004 Council decision that came into effect on 1 January 2005.[50] A subsequent Council decision in 2015 approved the implementation of the provisions on data protection andSchengen Information System to the UK.[51] The opt-out was criticised in the United Kingdom for hampering the country's capabilities to stoptransnational crime as a result of the inability to access theSchengen Information System.[52]
The United Kingdom secured its opt-out from the Charter of Fundamental Rights of the EU because it was worried that it might be used to alter British labour law, especially as relates to allowing more strikes.[53]
TheMajor ministry secured the United Kingdom an opt-out from theprotocol on theSocial Chapter of theMaastricht Treaty before it was signed in 1992.[54] TheBlair ministry abolished this opt-out after coming to power in the1997 general election as part of thetext of theTreaty of Amsterdam.[55][56]
The Edinburgh Agreement of 1992 included a guarantee to Denmark that they would not be obliged to join theWestern European Union, which was responsible for defence. Additionally, the agreement stipulated that Denmark would not take part in discussions or be bound by decisions of the EU with defence implications. TheTreaty of Amsterdam of 1997 included aprotocol that formalised this opt-out from the EU'sCommon Security and Defence Policy (CSDP). As a consequence, Denmark was excluded fromforeign policy discussions with defence implications and did not participate in foreign missions with a defence component.[57]
Following 2022Russia's invasion of Ukraine in February 2022, the Danish government announced that a referendum would be held on 1 June on abolishing its opt-out from this policy area.[58] The political partiesVenstre, theDanish Social Liberal Party and theConservative Party had historically supported ending the opt-out, with theSocialist People's Party and the leadingSocial Democrats changing their position to be in favour in the aftermath of the crisis. Right-wing parties theDanish People's Party and theNew Right, as well as the left-wingUnity List, continued to oppose the move. The result of the referendum was a vote of 66.9% in favour of abolishing the defence opt-out. Following the referendum Denmark formally notified the EU of its renunciation of its opt-out on defence matters on June 20, which became effective from 1 July.[59][60]
Following the announcement by the government of the United Kingdom that it would hold areferendum onwithdrawing from the European Union, an agreement was reached between it and the EU on renegotiated membership terms should the state vote to remain a member. In addition to a number of amendments to EU Regulations which would apply to all states, a legal guarantee would be granted to the UK that would explicitly exempt it from the treaty-stated symbolic goal of creating an "ever closer union" by deepening integration.[61] This guarantee was included in a Decision by theEuropean Council, with the promise that it would be incorporated into the treaties during their next revision.[62] However, following the referendum, in which the UK voted to leave the EU, per the terms of the Decision the provisions lapsed.
In 2009,Czech PresidentVáclav Klaus refused to completeratification of theTreaty of Lisbon unless the Czech Republic was given an opt-out from theCharter of Fundamental Rights, asPoland and the United Kingdomhad been with a Protocol to the treaty. He stated that he was concerned that the Charter would allow the families ofethnic Germans who were expelled from territory in modern-day Czech Republic after theSecond World War to challenge the expulsion before the EU's courts.[63] However, legal experts have argued that the laws under which the Germans were expelled, theBeneš decrees, did not fall under the jurisdiction of EU law as the Charter can not be applied retroactively.[64] In October 2009, EU leaders agreed to amend the protocol on Poland and the United Kingdom's opt-out to include the Czech Republic at the time of the next accession treaty.[65][66]
In September 2011, the Czech government formally submitted a request to the Council that the promised treaty revisions be made to extend the protocol to the Czech Republic,[67] and a draft amendment to this effect was proposed by theEuropean Council.[68] However, the Czech Senate passed a resolution in October 2011 opposing their accession to the protocol.[69] When Croatia'sTreaty of Accession 2011 was signed in late 2011, the Czech protocol amendment was not included. In October 2012, theEuropean Parliament Constitutional Affairs Committee approved a report that recommended against the Czech Republic's accession to the Protocol.[70] On 11 December 2012, a third draft of the European Parliament's committee report was published,[71] and on 22 May 2013[68] the Parliament voted in favour of calling on the European Council "not to examine the proposed amendment of the Treaties".[67][68][72] The Parliament did, however, give its consent in advance that a treaty revision to add the Czech Republic to the Protocol would not require a new convention.[73] In January 2014, followinglegislative elections the prior October that led to a change in government, the new Czech Human Rights MinisterJiří Dienstbier Jr. said that he would attempt to have his country's request for an opt-out withdrawn.[74][75] This was confirmed on 20 February 2014 by the new Prime MinisterBohuslav Sobotka, who withdrew the request for an opt-out during a meeting withPresident of the European CommissionJosé Manuel Barroso[76][77][78][79] shortly after his newly elected government won the confidence of Parliament.[80] In May 2014, the Council of the European Union formally withdrew their recommendation to hold anIntergovernmental Conference of member states to consider the proposed amendments to the treaties.[81][82][83][84]
