Catalonia's non-vote on independence that matters

The stars of the Catalonia independence flags wink in the sun from the city's balconies as thousands of volunteers below prepare for their improvised ballot.

But isn't it odd to be in Barcelona reporting on a non-referendum on independence - a vote on Sunday which has no legal weight? Initially it was dismissed by Spanish unionists as nothing more than a big "opinion poll".

But this is unprecedented for modern Spain, one of the eurozone's biggest states and still grappling with its economic crisis. Nobody really knows quite where this will go ultimately.

A clue to the importance of the vote is the fact that the government in Madrid has tried twice to block it in the courts but the "N9" (ninth of November) tide just keeps running.

Try telling the pro-independence activists, pressing free newsletters on passengers outside Barcelona's metro stations, that their planned mass expression of will is a meaningless gesture.

Voters are being registered by the hour at temporary booths, while polling stations are being set up in secondary schools in areas where normal official venues are off-limits under electoral laws.

The organisers expect as many as 1.5 million people to vote, and if they get out the numbers to support the vote for independence, can Spain reasonably ignore the result?

I will be talking to people on both sides and none.

I'll be asking local nationalists what hurts the most, but also about the wisdom of fracturing one of the eurozone's biggest countries, and the realistic prospects for a new small country deep inside the eurozone.

"There is no turning back," a source close to the Catalan government told me as I looked at the Scottish referendum poster on his office door.

"We wish we had a prime minister like David Cameron, who could persuade us to be Spaniards, but this is not a democracy. All we hear is 'no, no, no'."

As for the unionists, how does it feel when people around you want an exit from Spain and what, if anything, could Madrid do now to bring the Catalans back on board?

I'm here to test the temperature, of course. They say people in Barcelona only fight over football, not politics - but how high do feelings run?

There is no sign of any special security measures on the streets of Barcelona, where life bustles on as usual, though Madrid has deployed an extra 500 police to protect government buildings.

According to my source, the Catalan government does not expect any trouble on Sunday, although provocations by the Spanish far right can't be ruled out.

But these are dramatic days for Catalonia.

"No, this vote is not about strengthening our negotiating position," my source said. "There is no turning back."

Follow my blog on Tumblr and Twitter as I report on this fascinating vote. Join in the conversation with questions if you see me live-tweeting discussions.