SPANISH eyes will be on Luxembourg today where the European Court of Justice (ECJ) is expected to deliver a ruling on the immunity of jailed Catalan independence leader Oriol Junqueras.

He is serving a 13-year prison sentence handed down by the Supreme Court in October for his part in the 2017 independence referendum in Catalonia, but his lawyers claim he has legal immunity after being elected as an MEP in the European Parliament elections in May.

Spanish authorities claim the president of the Republican Left of Catalonia (ERC) had not been able to take the oath of office – they stopped him leaving “preventative detention” to swear it in Madrid – so he does not have MEP status.

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However, the ECJ’s advocate-general has already found in Junqueras’s favour on that score and has rejected Spain’s arguments, but his non-binding opinion also found that the Catalan ceased to be an MEP when he was sentenced after an eight-month trial.

Although non-binding, the advocate-general’s opinions are usually followed by the court. Should it find in Junqueras’s favour, it could benefit former Catalan president Carles Puigdemont, who is in exile in Brussels along with ex-ministers Antoni Comin and Luis Puig, and Clara Ponsati, who is in Scotland.

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Puigdemont, who was also elected an MEP in May, has already launched his own legal challenge and demanded to take his seat in the parliament.

Pedro Sanchez, Spain’s prime minister-in-waiting, is likely to be watching today’s ECJ ruling closely, given that talks between the ERC and his own Socialist party (PSOE) over his investiture have stalled.

Although he has reached a coalition deal with the left-wing, anti-austerity party Podemos, he still needs backing from smaller parties and the abstention of the ERC to become prime minister.

The republicans have been careful not to commit to any deal with Sanchez which could be seen by Puigdemont’s political grouping Together for Catalonia (JxCat) as a sell-out.

A Brussels court has already postponed until February the cases of Puigdemont and the other exiles.