40° 24' N , 3° 42' E

They call it "the red effect". It has spread down Spanish streets on the torsos of hundreds of thousands of fans wearing the shirt of the national soccer team, La Roja or "The Red", and threatens to over-run even the most obdurately separatist corners of the country. On nights when the team notches up another World Cup victory it turns into a musical chant: "I am Spanish! Spanish! Spanish!" they shout joyfully. "I am Spanish! Spanish! Spanish!"

Spaniards cannot recall an outpouring of national pride similar to that provoked by the country's first-ever appearance in the World Cup final today. "Not since the Spanish civil war have there been so many flags in the streets," El País newspaper reported as Madrid prepared for an all-night party if La Roja beat Holland in South Africa this evening.

Indeed, Spain's red and gold flag still reminds some people of the civil war of the 1930s, more particularly, of the 36-year dictatorship of Francisco Franco, leader of the pro-fascist Nationalists, that followed it. Few countries in Europe, except Germany, have such an instinctive mistrust of patriotism.

Such an outpouring of national pride also raises challenging questions about Spain's vision of itself. This is a "nation of nations" according to some, who see Catalonia and the Basque country as unrecognised nations which, like Scotland, deserve their own football teams. Spain oppresses other nations, according to separatists, including to the Basque terror group Eta – which exacts its revenge in blood. The country's constitutional court disagrees. "Our constitution recognises no nation but Spain," it affirmed on Friday in a stern rebuke to Catalans who hoped a new autonomy statute might formally allow them to be known as a nation within Spain.