Last week, the EU Court of Justice (CJEU), took a significant step towards protecting against human rights violations in the operation of the European Arrest Warrant.

The ruling comes in response to an Irish Court refusing extradition to Poland because of concerns that attacks on judicial independence in the country, which have been at the centre of the rule of law procedure triggered by the European Commission against Poland in January 2016.

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The Polish government had sought the extradition of Arthur Celmer - a Polish national - from Ireland, for alleged drugs violations. Because independence of the judiciary is an essential component of the fundamental right to a fair trial, the Irish court said it could not presume that Poland would uphold Celmer's right to a fair trial.

The law governing the European Arrest Warrant does not explicitly permit a member state to refuse to extradite a person if there is a risk of a human rights violation. And practice had long been for most EU member states to turn a blind eye and surrender persons even if such a risk existed.

In 2016, the CJEU took a first step by ruling that a person could not be extradited if there was a risk that the person would be subject to torture, cruel, inhuman or degrading treatment, for example because of prison conditions.

Last week's judgment is a step further which places human rights at the heart of the European Arrest Warrant system.

The CJEU affirmed the right of the Irish court to refuse to extradite if it finds a "real risk" to the person's right to a fair trial because of attacks on judicial independence.

And if the EU finds Poland in violation of their obligations to respect the rule of law, then extraditions under the European Arrest Warrant must cease altogether.

Two steps

Until that time, national courts must apply the two-step test that the CJEU created in 2016 – first, assess whether systemic deficiencies in the requesting state threaten the right to a fair trial in general; and second, assess whether these deficiencies impact both the court overseeing the case, and the case itself.

The CJEU took the opportunity to state that an independent judiciary is a core EU value, and that the judiciary must be protected against "external interventions or pressure liable to impair the independent judgment of its members and to influence their decisions".

This represents a clear warning to the Polish government to cease its attacks on the judiciary – and takes a stance against a pervasive trend across the EU towards curbing the independence of the judiciary.

But the implications of the ruling are broader even than this critical issue.

In June Fair Trials launched a report showing the extent to which the European Arrest Warrant, the EU's fast-track extradition system, is being abused by EU member states, putting at risk the lives and rights of ordinary people.

Adopted in the wake of the 9/11 attacks, the European Arrest Warrant was designed to help tackle complex, cross-border crimes by speeding up the process of bringing fugitives to trial or, if already convicted, to prison.

But, as our work has consistently shown, it is all-too-often inappropriately used for small offences or to investigate people rather than to bring them to trial, resulting in people being unfairly dislocated from their families, jobs and lives.

The Celmer judgment asserted that it is the responsibility of courts across the EU to assess the human rights situation in countries requesting extradition.

Before this, many courts argued that they were bound to apply the principle of "mutual trust", which is a presumption that fundamental rights are being observed by other EU member states.

But the CJEU made clear that this presumption is rebuttable, and courts must make an assessment where there is evidence that human rights are not being respected in countries seeking extradition under the European Arrest Warrant.

The judgment also has significant implications for the EU's legislative agenda.

Reform of the European Arrest Warrant legislative framework, which the European Commission has resisted despite repeated calls from the European Parliament, is now needed to ensure that EU member states all take steps to implement the CJEU's judgment consistently.

Beyond the European Arrest Warrant, the judgment casts a shadow over the legitimacy of the recent proposals of the EU commission to create a new judicial cooperation tool, the "European Production Order", intended to give prosecutors and judges the power to get hold of electronic data (both metadata and content data) held by companies, even if that data or the company is located in another member state – with no assessment by the judicial authorities of that other country.

The CJEU firmly stated that judicial cooperation means judicial review on both sides.

The future of this new tool, due to be debated in the European Parliament, now looks to be more uncertain than ever.

Laure Baudrihaye-Gerard is a senior lawyer responsible for law and policy at Fair Trials