The Supreme Court will shortly finalise questions for the European Court of Justice about Brexit’s potential impact on the extradition of EU citizens to the UK.

If the European court agrees to fast-track the case it could make a decision within three months. Given the importance of the issues raised, other EU states are likely to make oral submissions.

The core issue is whether a European Union state must refuse to extradite an EU citizen to the United Kingdom if that person will remain imprisoned there after the UK leaves the EU, in March 2019. This has implications for the UK’s efforts to extradite citizens not just from Ireland but also from other EU states, and it may also affect other areas of law.

As part of its drafting of the questions for the European court, the five-judge Supreme Court on Tuesday asked lawyers for the State for information about 20 High Court cases that are on hold pending the European decision. Three of them concern people who are in custody. Further extradition requests from the UK are expected before Brexit, the court heard.

Tax fraud

Earlier this month the Supreme Court said it had decided to refer the issues to the European Court of Justice because no country had yet left the EU. They arose in the case of Thomas Joseph O’Connor (51), a construction-company director with an address at Cloughbeirne, The Walk, Roscommon, who is wanted in the UK in connection with a £5 million tax fraud.

In January 2007, after a six-week trial at Blackfriars Crown Court, in London, Mr O’Connor was sentenced to 4½ years in prison for defrauding HM Revenue & Customs, the UK tax authority. But he returned to Ireland – he now also faces charges of absconding and breaching his bail in England – where he was arrested under a European warrant in 2014. The High Court ordered his extradition in December that year, and after he failed to overturn that ruling in the Court of Appeal he took his case to the Supreme Court.

His barristers, Michael Forde SC and James O’Reilly SC, argued that Ireland was being asked to surrender an EU citizen to the UK when it was unclear whether the extradition would be subject to EU or UK law. The Minister for Justice argued that his extradition should rely on current law, opposing a referral to the European Court of Justice.

In its preliminary ruling, on February 1st, the Supreme Court said that before deciding whether to hear Mr O’Connor’s appeal it wanted the European court to decide the Brexit-related issues.

The Chief Justice, Mr Justice Frank Clarke, said it was in the interests of all “that certainty be brought to this area of law as quickly as possible”.