On 23 April 2026, the ECJ held in Case C-528/24 (Boothnesse) that a possible infringement of the speciality rule - a basic concept in extradition law - by the issuing State does not constitute, in itself, a ground for the executing judicial authority to refuse the execution of an extradition arrest warrant.

Background of the case and question examined

In the dispute in the main proceedings, three defendants objected to their extradition from Ireland to the United Kingdom (UK) on the ground that the arrest warrant issued for the prosecution of fraud did not include their conviction for contempt of court, as the defendants had failed to comply with restraint orders; the UK court had imposed an imprisonment of six months on each defendant for this act. However, according to the UK authorities, "contempt of court" is classified as a civil matter and not as a criminal offence, therefore, the arrest warrant could not include this act.

Given a reference for preliminary ruling from the Irish Supreme Court, the ECJ had to examine whether, in such situations, Art. 625 of the Trade and Cooperation Agreement concluded between the EU and the United Kingdom of Great Britain and Northern Ireland (TCA) requires or permits the Irish judicial authority to refuse the execution of the UK arrest warrant. Art. 625 TCA governs the speciality rule in cross-border extradition and surrender proceedings between EU Member States and the UK. It ensures that a surrendered person is not prosecuted, sentenced, or detained for any offense committed prior to their surrender, other than the specific crime for which they were handed over. For further details → eucrim 4/2025, 282-283 summarising the Advocate General's opinion in the case.

The ECJ's decision and reasoning

According to the ECJ, the fact that the requested persons who are the subject of arrest warrants issued on the basis of the TCA with a view to bringing criminal prosecutions for a criminal offence has been sentenced, in the issuing State, to a penalty involving deprivation of liberty for another offence, which is not the subject of that arrest warrant, does not permit, in itself, the competent judicial authority to refuse to execute that arrest warrant. This follows from a literal, contextual and teleological interpretation of the provision:

• The wording of Art. 625 TCA does not indicate that the executing judicial authority is required, before ruling on the surrender of the requested person, to check whether the authorities of the issuing State are required to comply with the speciality rule or whether those authorities in fact comply, in practice, with that rule;
• The extradition refusal grounds are set out in Arts. 600 and 601 TCA which do not include a reference to Art. 625 TCA;
• Allowing the executing judicial authority to conduct a general review of whether the issuing authorities upheld the requirements of the TCA would impede the efficiency of the surrender mechanism established by the TCA.

However, the ECJ acknowledged that the infringement of the speciality rule must be seen in the context of the right not to execute an arrest warrant if there are valid reasons for believing that there would be a real risk to the protection of that person’s fundamental rights if he or she were surrendered to the United Kingdom (Arts. 524(2), 604 lit. c) TCA). The fundamental rights in Art 47 CFR would be infringed, for example, if the requested person did not have, in the issuing State, any legal remedy enabling him/her to invoke an alleged breach of the speciality rule. It is finally for the referring court to examine whether the requested persons' fundamental rights risk to be infringed in the UK.