A moment of triumph — the declaration of Europe's newest independent state — has quickly become the cold reality of what Catalonia's separatists were always likely to face in their historic collision with Spain.

Within hours of the parliament in Barcelona voting to break away on Friday, the would-be Catalan Republic was hit by might of the Spanish state.

Rather than leaving Catalan President Carles Puigdemont and his deputies running their own affairs, it has left them with little real power and facing potential arrest in the coming days as Prime Minister Mariano Rajoy's authorities move in.