I am a Catalan businessman, the son of labourers. My mother emigrated from Murcia, a Spanish province, and my father was born in Badalona, the third most populated city in Catalonia. We spoke both Catalan and Spanish at home, like the large majority of Catalans with Spanish roots. I am 41 years old, I live in Barcelona. I am married with a seven-month-old son and two other children (stepchildren) whom I love as if they were my own. I am the 10th president of Òmnium Cultural – an organisation set up to promote the Catalan language and spread the region’s culture. It’s a position I hold completely voluntarily. I have been in prison for 50 days now, without a trial, accused of sedition, along with Jordi Sànchez, former president of the Catalan National Assembly.

We are deprived of our freedom for having made use of our right to free expression and demonstration, for the simple act of publicly and democratically defending the right of Catalonia to decide its future as a people at the polls, like Quebec and Scotland did with the mutual agreement of the governments of Canada and the UK.

Timeline Eight key moments in the Catalan independence campaign Show Spain’s constitutional court strikes down parts of a 2006 charter on Catalan autonomy that had originally increased the region’s fiscal and judicial powers and described it as a “nation”. The court rules that using the word “nation” has no legal value and also rejects the “preferential” use of Catalan over Spanish in municipal services. Almost two weeks later, hundreds of thousands protest on the streets of Barcelona, chanting “We are a nation! We decide!” At the height of Spain’s economic crisis, more than a million people protest in Barcelona on Catalonia’s national day, demanding independence in what will become a peaceful, annual show of strength. The pro-independence government of Artur Mas defies the Madrid government and Spain’s constitutional court by holding a symbolic vote on independence. Turnout is just 37%, but more than 80% of those who voted - 1.8 million people - vote in favour of Catalan sovereignty. Carles Puigdemont, who has replaced Mas as regional president, announces an independence referendum will be held on 1 October. Spain’s central government says it will block the referendum using all the legal and political means at its disposal. The Catalan parliament approves referendum legislation after a heated, 11-hour session that sees 52 opposition MPs walk out of the chamber in Barcelona in protest at the move. Spain’s constitutional court suspends the legislation the following day, but the Catalan government vows to press ahead with the vote. Police arrest 14 Catalan government officials suspected of organising the referendum and announce they have seized nearly 10 million ballots destined for the vote. Some 40,000 people protest against the police crackdown in Barcelona and Puigdemont accuses the Spanish government of effectively suspending regional autonomy and declaring a de facto state of emergency. Close to 900 people are injured as police attempt to stop the referendum from taking place. The Catalan government says 90% voted for independence on a turnout of 43%. Spanish government takes control of Catalonia and dissolves its parliament after secessionist Catalan MPs voted to establish an independent republic. Spanish prime minister, Mariano Rajoy, fires regional president, Carles Puigdemont, and orders regional elections to be held on 21 December.

But we have not committed any crime. The Spanish government has put us in prison for our ideas and opinions, for having organised mass peaceful, festive and family-oriented demonstrations, the images of which have been seen around the world. Today we are in prison not for being dangerous individuals or having committed fraud, theft or murder, but for our political ideas, shared by the 80% of Catalans who are in favour of holding a referendum on self-determination. There were more than 900 victims of Spanish police violence as they exercised their right to vote on 1 October.

The repressive spiral of the Spanish government has extended to the members of the government of the Generalitat. Half went into exile in Belgium and the other half were immediately imprisoned. It was an unprecedented event in modern Europe: half of a democratically chosen government was sent to prison. On Sunday, as we draw closer to the Catalan election on 21 December, the former Catalan vice-president Oriol Junqueras, former cabinet member Joaquim Forn, Jordi Sànchez and myself as leaders of civic groups have been refused bail by Spain’s supreme court. The judge ruled that he believed there was a risk of criminal reiteration.

Today, Òmnium Cultural has more than 90,000 members and is the main civic-cultural organisation in Catalonia. It was founded in 1961 by five businessmen to defend Catalan language and culture. The Franco dictatorship banned Òmnium from 1963 to 1967. Forty years later, its president has been imprisoned. From its origins until the present day, Òmnium has had a single objective: to guarantee social cohesion in Catalonia.

We keep our firm commitment to share, from a perspective of mutual respect, this cultural, ideological, religious and social diversity. And under the protection of the universal declaration of human rights, defend the right to the self-determination of Catalonia, always through democratic and peaceful means.

European institutions and leaders cannot continue to look the other way, failing to demand that our rights are respected and restored. The founding fathers of the EU built the project on the principles of dialogue, peace and democracy. Those have been clearly violated. The Catalan problem is a European problem. Failing to stand up for these principles could have dire economic, political and social consequences over the short-, medium- and long-term for millions of European citizens.

We proclaim our innocence and our status as prisoners of conscience and insist that the Spanish government free us immediately. We must begin a cooling-off period of dialogue between the parties, in which I promise to dedicate the best efforts of Òmnium Cultural, as we have always done until now.

Catalonia and Spain form part of the EU and everything that occurs from now on will affect the entire union. We are convinced that no one should renounce their responsibility. More than ever the EU must return to its roots: dialogue, peace and democracy. Civic society is calling for this, and it is the duty of political leaders to listen to the petitions of their fellow citizens.

• Jordi Cuixart is the president of Òmnium Cultural