An Irish judge’s ruling in an extradition case has called into question Poland’s continued participation in the European Arrest Warrant (EAW) scheme, and perhaps even its role in the EU as a whole.

At root are the controversial reforms to the Polish judicial system introduced by the governing PiS (Law and Justice) party following its election in 2015. Two aspects of the reforms in particular - the assumption by the legislature of the power to make judicial appointments, and the merging of the justice ministry with the main prosecuting agency - led Justice Aileen Donnelly to refuse an extradition request and to refer the case (concerning Artur Celmer, an alleged drug trafficker) to the European Court of Justice (ECJ), citing “what appears to be the deliberate, calculated and provocative legislative dismantling by Poland of the independence of the judiciary, a key component of the rule of law”. Should the ECJ conclude that Poland’s courts no longer meet minimum EU standards, it may lead the Commission to suspend funding to Poland. The Commission has previously expressed its grave concerns about the “clear risk of a serious breach of the rule of law in Poland” and in December 2017 required the PiS to respond within three months, a deadline that expires next week.

Even if the nuclear outcome - suspension of funding and exclusion from EU legal processes - is avoided, the effect on the EAW scheme could be dramatic. Even before the ECJ rules on the matter, one can expect challenges to Polish extradition requests to rely on Justice Donnelly’s conclusion that PiS’s power grab has undermined the fundamental principle of mutual trust. Bearing in mind that more EAWs adjudicated by the English courts originate from Polish judicial authorities than from any other member state – over 15,500 since 2009 and nearly 2000 in 2016-17 - the effect is likely to be significant.

Obviously, it remains to be seen whether the courts here will entertain such challenges absent clear direction from the ECJ; practitioners’ expectations may be tempered by the sometimes inventive ways that judges approve the validity of requests. Nevertheless, the Celmer decision represents a significant development in extradition, and of course comes at a time of uncertainty and flux created by the UK’s decision to leave the EU. HMG has expressed its commitment to remaining in the EAW scheme post-Brexit, but it is becoming increasingly unclear what any surviving scheme will look like.