A Supreme Court judge in Spain has said that the Speaker of the Catalan parliament can be released on bail pending an investigation into her role on the banned push for independence.

Carme Forcadell has spent the night in prison, accused of being involved in a concerted attempt to establish a republic of Catalonia.

The court has set bail conditions of €150,000. A pro-independence group is expected to meet the cost to allow her to leave prison today. 

Four other senior MPs avoided a jail sentence, but must pay a bail bond of €25,000 in the next week.  

The supreme court had summoned them to answer charges of rebellion after they enabled an 27 October declaration of independence that prompted the Spanish government to dissolve the Catalan parliament and sack the regional administration.

Judge Pablo Llarena wrote in last night's ruling: "All the accused ... have expressed that either they renounce future political activity or, those that remain active, will in future renounce any actions outside the constitutional framework."

The judge's decision to reject prosecutors' requests to jail them gives the separatists, whose leader Carles Puigdemont went into self-imposed exile in Belgium last week, some breathing space as lower courts have been steadily tightening the legal noose.

Eight former members of the Catalan government and the leaders of the two main pro-independence grassroots groups remain in custody awaiting trial at the High Court on charges of rebellion and sedition.

Yesterday, the high court rejected an appeal presented by their lawyers for their release, a court spokeswoman said.

The high court last week issued an arrest warrant on rebellion charges for Mr Puigdemont, the former regional government president, and four former members of his cabinet who are with him in Brussels.

After the ruling, Mr Puigdemont tweeted: "Carme Forcadell will spend the night in prison for allowing a democratic debate. For allowing speaking and voting! That's Spanish democracy for you."