The Supreme Court has decided to urgently refer questions relating to the extradition of a man to the UK to the European Court of Justice.
Thomas Joseph O'Connor, of Cloughbeirne, the Walk, in Roscommon, is wanted in the UK over his role in a £5 million pound tax fraud.
He was sentenced in his absence in at Blackfriars Crown Court in 2007 to four-and-a-half years in jail.
He failed to turn up to the sentencing hearing and is also wanted for breaching his bail.
Mr O'Connor has challenged his extradition on a number of grounds.
In this latest appeal, he is challenging his extradition on the basis that his rights could be violated because of the UK's decision to leave the EU in March 2019.
His lawyers argue that his rights as a European Union citizen, surrendered to another EU jurisdiction on foot of a European Arrest Warrant, will no longer be capable of being enforced under European law.
He also argues his surrender is no longer legally permissible.
The Supreme Court was asked to decide if he should have permission to pursue an appeal against a High Court decision last year that he should be surrendered to the UK.
The court was previously told 20 extradition cases to the UK are held up, pending the decision in this case.
In the court's judgment, Chief Justice Frank Clarke said there must be no one in Ireland who was not now aware that there could be significant complications arising in a whole range of areas as a result of Brexit. He said this application concerned one such potential issue.
The court heard that it was highly probable that if he was surrendered to the UK, Mr O'Connor would continue to be imprisoned there beyond 29 March 2019, when the UK is due to withdraw from the EU.
His lawyers argue that Ireland is being asked to surrender an EU citizen in circumstances where the legal framework under which that citizen may come to be governed was at significant risk of no longer being subject to European law.
His lawyers claim his surrender is not possible and will remain impossible until there is sufficient clarity about the post-Brexit regime.
Lawyers for the Minister for Justice argue that the proper way to approach these issues is to look at what the law says now and that hypothetical questions about what may or may not happen in the context of Brexit are not relevant to whether or not Mr O'Connor should be surrendered now.
The Supreme Court said it was a matter of speculation and could in reality be nothing else to consider what rights Mr O'Connor might have post-Brexit, because it would depend on the terms of any arrangements entered into between the EU and the UK and also the laws of the UK and decisions of the UK courts.
Mr Justice Clarke said the court must conclude that there was an issue of European law arising in these proceedings, which could properly form the basis of an appeal to this court.
He said the point was novel and had not been decided by the Court of Justice before, hardly surprising, he said, as there had never been a case before of a country leaving the EU.
He said it was necessary to grant Mr O'Connor permission to appeal his surrender to the UK, in order to refer the issue to the Court of Justice.
The Chief Justice said the court had been informed there were 20 High Court cases pending the decision in this application.
He said the court was also mindful of the fact that the principle advanced in this case, might have some effect in other areas of law. He added it had the potential to affect the relations between other countries and the UK in a range of areas.
Man’s challenge over extradition to UK due to consequences of Brexit sent to European Court of Justice pic.twitter.com/1uQev4MJkt— RTÉ News (@rtenews) February 1, 2018
Mr Justice Clarke said the Court was "minded" that the reference to the Court of Justice should be made at the earliest possible date and to invite the court to deal with the matter in the "most expeditious" manner possible.
He said it was in the interests of all concerned, that certainty be brought to this area of the law as quickly as possible. However, he said that certainty could only be brought about by the Court of Justice.
The matter is listed for a short hearing on 13 February to decide the questions to be referred.
The Supreme Court set out its own version of the questions but will hear submissions from both sides before finalising them.
The Supreme Court has suggested that the Court of Justice should be asked if, in the context of Brexit, a requested state is required to decline to surrender a person to the UK under a European Arrest Warrant, whose surrender would otherwise be permitted, in all cases, in no cases or having regard to the particular circumstances of the case.
It also wants to ask the Court of Justice what criteria should a court assess to determine whether surrender is required, and whether or not the court in the requested state can postpone finalisation of a request to await greater clarity about what is to happen after the UK leaves the EU.