The Treaty of Amsterdam gives the United Kingdom the right to decide on its involvement in EU legislation in the area of justice and home affairs on a case-by-case basis (opt-in/opt-out). Alongside police and judicial cooperation on criminal matters, this applies to the external borders, asylum, migration and cooperation on civil matters. Thus, the United Kingdom opted out of the Blue Card Directive, the Directive on the status of third-country nationals who are long-term residents and the Directive on the return of third-country nationals, for example. This means that the authorities cannot access the Visa Information System.
At the same time, however, the British government benefits from individual legislative acts to combat and prevent undesired migration. British authorities are not part of Frontex, yet take part in Frontex measures via bilateral agreements (e.g. joint deportations).
Likewise, the UK does not recognise the Schengen acquis and is thus not obliged to abolish checks at internal borders. Yet the British law enforcement agencies do use individual provisions from the Schengen acquis – such as mutual assistance in criminal matters and (to a limited extent) access to the Schengen Information System. Following a “block” opt-out in 2014, the UK now once again also recognises the “Prüm acquis” on the exchange of information and operational cooperation between police forces.
The “block” opt-out calls into question the UK’s participation in the Europol agency, whose current Director is from the UK. When opting back in to individual measures, the UK government only opted in to the 2009 Europol Regulation. However, just before the Brexit referendum, the European Parliament and the Council adopted the new Europol Regulation, which will come into force on 1 May 2017 and replace all previous decisions. It seems hardly conceivable following the Brexit vote that the new government would decide to adopt this Regulation. Thus, by next spring at the latest, the UK would need to completely withdraw for the time being from Europol.
This text first appeared here.