Catalan leader Carles Puigdemont has threatened to explicitly declare independence if no talks are offered, in a letter to Spain's prime minister.

Minutes before a deadline to back down on the independence bid expired, Mr Puigdemont warned Mariano Rajoy that if Spain's government continued to “impede dialogue and continues its repression”, Catalonia's parliament would proceed to hold a vote on declaring independence from Spain.

The Catalan leader declared independence in an address to the regional parliament last week, but then immediately suspended it and challenged Spain to hold negotiations.

Article 155 has not been used in the four decades since democracy was restored at the end of General Francisco Franco's dictatorship.

Catalans would consider the application of the measure an “invasion” of the region's self-government, while Spain's central authorities are portraying it as an undesired move, yet a necessary one, to restore legality after Mr Puigdemont's government pushed ahead with a banned referendum that violated the country's constitution.

More than 40 per cent of Catalonia's 5.5 million eligible voters cast ballots in the illegal 1 October referendum as police used violence to try to enforce a court order to stop it from going ahead. Opponents boycotted the vote.

Catalan officials say that hundreds of people were injured in police violence, while Spanish authorities say hundreds of police officers were also hurt and the use of force was proportional to the resistance they met.

The separatists declared an overwhelming victory despite the boycott by opponents and on the grounds that it was illegal and lacked basic guarantees such as an independent electoral board.

Spain's government has said it would be willing to hold off on applying Article 155 if the Catalan separatist leader were to call a snap regional election. But Catalan officials have ruled that out.

The Catalan government's international affairs director Raul Romeva told reporters in Brussels that Catalonia's banned 1 October secession referendum gave the region's separatist government a mandate to declare independence from pain.

Catalonia independence referendum: Riot police clash with voters Show all 17 1 /17 Catalonia independence referendum: Riot police clash with voters Catalonia independence referendum: Riot police clash with voters A man faces off Spanish Civil Guards outside a polling station in Sant Julia de Ramis Reuters Catalonia independence referendum: Riot police clash with voters Riot police form a security cordon around the Ramon Llull school in Barcelona EPA Catalonia independence referendum: Riot police clash with voters Riot police evict a young woman during clashes between people gathered outside the Ramon Llull school in Barcelona EPA Catalonia independence referendum: Riot police clash with voters Spanish Civil Guard officers break through a door at a polling station in Sant Julia de Ramis Reuters Catalonia independence referendum: Riot police clash with voters Spanish National Police clash with pro-referendum supporters in Barcelona on Sunday AP Catalonia independence referendum: Riot police clash with voters Crowds raise their arms up as police move in on members of the public gathered outside to prevent them from voting in the referendum at a polling station where the President Carles Puigdemunt will vote later today Getty Catalonia independence referendum: Riot police clash with voters People confront Spanish Civil Guard officers outside a polling station Reuters Catalonia independence referendum: Riot police clash with voters Three man hold each other as they try to block a Spanish police van from approaching a polling station AP Catalonia independence referendum: Riot police clash with voters A woman shows a ballot to a Spanish Civil Guard officer outside a polling station Reuters Catalonia independence referendum: Riot police clash with voters A man wearing a shirt with an Estelada (Catalan separatist flag) and holding carnations faces off with a Spanish Civil Guard officer Reuters Catalonia independence referendum: Riot police clash with voters Police try to control the area as people attempt to cast their ballot at a polling station in Barcelona Getty Catalonia independence referendum: Riot police clash with voters A man is grabbed by officers as police move in on the crowds Catalonia independence referendum: Riot police clash with voters Two women argue with a Spanish National policeman during clashes between Catalan pro-independence people and police forces at the Sant Julia de Ramis sports centre in Girona EPA Catalonia independence referendum: Riot police clash with voters Sant Julia De Ramis in Spain Getty Catalonia independence referendum: Riot police clash with voters Confrontation outside a polling station in Barcelona, where police have tried to stop people voting AFP/Getty Images Catalonia independence referendum: Riot police clash with voters A Spanish National Police officer aims a rubber-bullet rifle at pro-referendum supporters in Barcelona AP Catalonia independence referendum: Riot police clash with voters Riot police clashed with voters as polls opened in Barcelona Sky News

PDeCAT's Pascal said that the only election on the table would be a vote to elect a constituent assembly in the next few months once the path to independence gets underway.