According to EU law, third-country citizens who are family members of EU citizens and possess a residence card need not obtain an entry visa for travelling to another EU member state. In situations of abuse or fraud, for example in the form of marriage fraud, states can introduce some restrictions so as to limit this freedom of movement. The United Kingdom has decided to do so.

Mr. McCarthy enjoyed dual citizenship (Ireland and the UK) and lived in Spain with his family - his wife (Colombian citizenship) and daughter (same citizenship status as her father). Every six months, wanting to enter the UK, the family had to apply for a family permit of entry, even though Mr. McCarthy's wife does have an EU residence card. The family decided that such rules infringe their right of freedom of movement.

The British court sent an inquiry to the Court of Justice of the European Union, asking if the rules introduced by the UK are in accordance with EU law.

In his opinion, Advocate General Maciej Szpunar came to the conclusion that the standing EU directive on freedom of movement was to be applied when a citizen of the EU departs from his or her country, and so exercises their right of freedom of movement, and then returns to the country together with family members. This conclusion is in accordance with hitherto decisions of the CJEU.

As for the central question asked by the British court, Advocate General Szpunar stated that introducing a compulsory entry permission application process for third-country members of EU citizens' families was not done so by the UK on the basis of an earlier establishment of abuses, and was instead general and preventative in nature. Therefore, because abuse or fraud is necessary for the imposition of such restrictive measures, the entry application requirement in this particular case breached EU law.

The Advocate General concluded that such practice is equivalent to visa requirements, and is therefore contradictory to EU law and the right of freedom of movement.