The United Kingdom and Ireland have participated in certain aspects of the Schengen Agreement, such as the Schengen Information System (SIS), since 2000 and 2002 respectively. At many external border crossings, there are special lanes for EU, EEA and Swiss citizens (and their family members) and other routes for all travellers, regardless of nationality.  At some external border crossing points, there is a third type of route for Travellers who are Annex II nationals (i.e. visa-exempt nationals of non-EU/EEA/Swiss countries).  Although Andorran and San Marino citizens are not eu or EEA citizens, they can still use the special channels provided for EU, EEA and Swiss citizens.  British citizens will not be able to use the EU route after Brexit under the current state of the rules, unless such a right is negotiated in the Brexit agreement with the EU. The November 13 attacks in Paris, in which 130 people were killed, triggered an urgent overhaul of the Schengen Agreement. A short-stay visa costs €60 (€46; $66), but only $35 for Russians, Ukrainians and citizens of some other countries under visa facilitation agreements. Four non-EU countries – Switzerland, Liechtenstein, Norway and Iceland – are members of the region. Countries outside the territory impose border controls on travelers from the Schengen area, but many have visa-free travel arrangements as members of the EU or countries that have signed visa-free travel agreements with Schengen states.
In 1999, the United Kingdom formally requested to participate in certain provisions of the Schengen acquis – Title III on police security and judicial cooperation – and in 1999 this request was approved by the Council of the European Union on 29 May 2000.  The UK`s formal participation in previously approved areas of cooperation was implemented by a 2004 Council Decision which entered into force on 1 January 2005.  Although the UK is not part of the passport-free Schengen area, it has nevertheless used the Schengen Information System, a government database used by European countries to store and disseminate information about people and goods. This has allowed the UK to exchange information with countries that are part of the Schengen Agreement, often at odds over prosecutions.  In 2020, the United Kingdom stated that it would withdraw from these agreements at the end of its transition period. Before concluding an agreement with a neighbouring country, the Schengen state must obtain the agreement of the European Commission, which must confirm that the draft agreement complies with the regulation. The agreement can only be concluded if the neighbouring country grants at least reciprocal rights to EEA and Swiss nationals residing on the Schengen side of the border area and accepts the return of persons who abuse the border agreement. Of the 27 EU Member States, 22 participate in the Schengen area. Of the five EU members that are not part of the Schengen area, four – Bulgaria, Croatia, Cyprus and Romania – are legally obliged to join the area in the future, while the other – Ireland – retains a derogation. The four Member States of the European Free Trade Association (EFTA), Iceland, Liechtenstein, Norway and Switzerland, are not members of the EU, but have signed agreements in conjunction with the Schengen Agreement. Three European micro-states that are not members of the European Union but are enclaves or semi-enclaves within an EU member state – Monaco, San Marino and Vatican City – are de facto part of the Schengen area. .