Spain's Constitutional Court has ordered the suspension of a Catalan parliament resolution approving a new independence referendum in September 2017, following a central government challenge.

The suspension is temporary for now and a standard part of the legal process when the Constitutional Court accepts a central government legal challenge related to one of Spain's 17 regions.

The Attorney General alleges the Catalan regional chamber's resolution contravenes a previous Constitutional Court ruling from 2015 on the same subject, in that case in reference to a separatist resolution in the Catalan parliament on November 9, 2015.

The government also says the new resolution contravenes two further Constitutional Court orders from 2016, also related to the regional chamber approving separatist measures.

The Catalan parliament now has 20 days to reply and the court has reminded the Speaker, Carme Forcadell, the Speaker's Committee, the First Minster, Carles Puigdemont, and the Catalan government of their duty to "prevent or stop" any measures designed to defy the court's orders, with the threat of criminal prosecution hanging over them if they fail to do so.

Yesterday, the National High Court in Madrid bailed four members of the separatist Popular Unity Candidacy (CUP) and one member of Podemos after they disobeyed an order to appear before judges in Catalonia last week over the burning photos of the King during the annual Diada Day celebrations on September 11.

Police stopped one coach full of supporters travelling to protest outside the court, to arrest two of the five CUP members, who were on board. The other three were arrested in Catalonia.

A lawyer for two of the accused said they had refused to answer the judge's questions and that it was "an insult to intelligence" that a democratic state was "persecuting" his clients "for the simple fact of burning a photocopy".

Catalan Republican Left (ERC, Esquerra) demanded the Home Secretary, Juan Ignacio Zoido, appear in parliament to explain why the police stopped the bus to arrest the two CUP members.