The president of Spain's Catalonia region, Artur Mas, signed a decree on calling an independence referendum on November 9.
The central government has said the vote would violate the constitution and has promised to block it.
Spain's Prime Minister Mariano Rajoy has called an special cabinet meeting to challenge the vote in the constitutional court.
The Plaza de Margaret Thatcher in the centre of Spain's capital has received a mixed response from politicians in the country.Read the full story ›
The Foreign and Commonwealth Office (FCO) has raised "serious concerns" after a Spanish Navy vessel wrongly claimed commercial ships off Gibraltar were in Spanish waters.
Spanish Ambassador Federico Trillo has been summoned to appear at the Foreign Office following the incident, which occurred in international waters.
The FCO says the Spanish vessel's actions constitute a breach of the UN Convention on the Law of the Sea.
Minister for Europe, the Rt Hon David Lidington MP, said: “I am extremely concerned by the actions of a Spanish Navy vessel which sought to redirect two commercial vessels heading to and from the Port of Gibraltar, wrongly claiming they were in Spanish waters.
“I condemn this provocative activity and urge the Spanish government to ensure that it is not repeated. Her Majesty’s Government will continue to take whatever action we consider necessary to uphold the interests of Gibraltar, its people, its security and economy."
Prime Minister David Cameron raised Gibraltar with Spanish Prime Minister Mariano Rajoy in the margins of an EU Council meeting.
He made it clear there must not be a repeat of last summer's disruption when the imposition of additional border checks by the Spanish led to long delays at the frontier.
A 23-year-old British man is recovering in hospital in Spain after he was trampled during Spain's San Fermin festival of running with the bulls in Pamploma.
Tom Hadfield fractured four ribs and a punctured lung after he was trampled on Tuesday morning. Speaking from hospital this morning he said:
"I've never experienced pain like this before. It's agony. I think a few of them trampled me. It's a miracle they didn't crush my skull or break my back."
"Afterwards I got up and carried on running for a bit. Then I started to get dizzy and found somewhere safe to keel over.
"Next thing I know I'm vomiting blood on the street and there is a big crowd around me. Then I passed out and woke up in the ambulance. Pretty scary. I thought I was paralysed."
Many people are injured every year in the festival, and 15 people are believed to have died since they started keeping records in 1910.
The author of a book on how to survive bull-running ended up in hospital this week after being gored by one of the ferocious animals.Read the full story ›
Two people have been gored in the annual running of the bulls festival in Pampalona after a lone bull sped ahead of the pack.Read the full story ›
Spain's famous San Fermin fiesta saw its first Running of the Bulls today, with four people hospitalised in the famous chase.Read the full story ›
People in Gibraltar feel "under siege" due to the territory being the subject of diplomatic wrangling between the UK and Spanish governments, the House of Commons' Foreign Affairs Committee has said.
"The combination of direct pressure on its border and sovereign waters as well as
diplomatic pressure at the EU, UN and NATO, have resulted in a feeling in Gibraltar of
being under siege," the cross-party committee's latest report says.
The committee accuses Spain of "aggressive policies" towards Gibraltar and says the Government "has responsibilities toward Gibraltar and cannot ignore actions by Spain that are intended to make the lives of Gibraltarians difficult".
The Government has rejected the suggestion from a committee of MPs that it needs to "get off the fence" and act more vigorously to protect British interests in Gibraltar.
A Government spokesman said: "This Government has never been on the fence when it comes to Gibraltar."
"We've been absolutely clear that we will never enter into arrangements under which the people of Gibraltar would pass under the sovereignty of another state against their wishes. And we protest each and every illegal incursion by Spanish state vessels into Gibraltar territorial waters."
A cross-party committee of MPs has called on the Government to threaten Spain with legal action over its treatment of Gibraltar.
The Foreign Affairs Committee also called for a "more robust" response to incursions into British territorial waters and urged ministers to "get off the fence".
The committee said ministers should now set out "naval and police options" to stop Spanish vessels entering British waters, as well as threatening to take Spain to the European Court for breaching EU treaty obligations.