MADRID, Sept 6 (Reuters) - Spain's government has asked the Spanish constitutional court to declare void a referendum law that Catalonia's separatist government is expected to pass later on Wednesday, Spain's deputy prime minister said. Catalan lawmakers are voting on a bill that will allow regional authorities to officially call an Oct. 1 referendum on a split from Spain, making concrete a years-long defiance of central authorities, who see the vote as illegal.
Spain plans to sue leading members of the Catalan Parliament over the proposed independence referendum in Catalonia.