CATALAN independence figures who have been in prison in Madrid for their trial over the 2017 referendum are expected to complete their return to jails in Catalonia today.

Oriol Junqueras, Raül Romeva, Jordi Sànchez, Jordi Cuixart, Joaquim Forn, Josep Rull and Jordi Turull have been detained for 20 months, mostly in the Brians 2 penitentiary outside Barcelona, but they had been moved to the Spanish capital for their trial.

They began their return journey to Barcelona on Monday with overnight stops at two institutions en route.

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This morning they were due to leave Valdermo prison, outside Zaragoza.

Female prisoners Carme Forcadell and Dolors Bassa will make the journey to Barcelona in a single trip today.

The male prisoners will be kept at Lledoners jail, where thousands of people gathered every night over the months of their pre-trial detention singing, cheering and waving torchlights.

Once in the Catalan establishments, the prisoners will once again be the responsibility of the Catalan police force Mossos d’Esquadra.

It is still not clear if they will all have to return to Madrid for the trial verdicts, which are expected in autumn.

Meanwhile, Spain’s Supreme Court has raised the possibility of taking the case of Junqueras – who has been elected as an MEP – to the European Court of Justice to clarify whether or not, as an elected member, he should have immunity.

Lawyer Andreu Van den Eynde, who represents Junqueras, lodged an appeal over the issue on June 16, saying he wanted to “ensure uniform application” of European law.

His client was not permitted to swear an oath to the Spanish constitution and Van den Eynde said this was a violation of his rights “to be chosen and to exercise without disturbances the tasks of political representation”.

The appeal calls for clarification on whether MEPs’ immunity is acquired when they are elected or when they collect their documentation once they have taken the oath.