- Video report by ITV News Correspondent Emma Murphy
Scores of Catalan farmers drove their tractors through central Barcelona as thousands took to the streets on Friday in the last rally ahead of an independence referendum that could tear the country apart.
Seven and a half million people in Catalonia will head to the polls on Sunday in a vote which has been condemned as illegal by Madrid.
Many in the region are angry that it generates almost a fifth of the country's GDP, contributing much more than they get back.
Catalonia also has historic differences - and its own language, culture and customs.
Those leading the fight risk jail for their actions but continued to urge would-be voters to defy the national government and cast their ballot.
Raul Romeva, from Together For Yes, told ITV News: "This is about democracy.
"We have the economy, we have the society, we have the people which is the most important, we have the determination.
"And we have the opportunity not only for Catalonia... this is an opportunity for the rest of Spain."
The Madrid-based Spanish government has maintained the ballot cannot and will not happen because it contravenes the constitution, which refers to "the indissoluble unity of the Spanish nation".
Ballot papers are being printed and stored in secret locations and dozens of local officials have been arrested.
Thousands of police have been brought in from around the country and housed on cruise ships in Barcelona's port amid warnings polling stations will be stormed and ballot boxes seized.
Acting on court orders, police have already confiscated about 10 million ballot papers and some 1.3 million posters advertising the referendum.
The Catalan regional government and local civic groups insist they are entitled to exercise their democratic rights and intend to do so regardless of the obstacles.
Catalan leaders, including regional president Carles Puigdemont, said on Thursday that senior European Union officials should step in and broker a political solution to the stalemate.
But European Commission vice president Frans Timmermans appeared to scotch that idea, saying on Friday that the constitution must be respected.
"That is the rule of law, you abide by the law and the constitution even if you don't like it," he said.