Hundreds of thousands of Catalans will take to the streets on Thursday, the National Day of Catalonia, to demand the right to hold a referendum on their future, with some hoping that the sudden surge in support for Scottish independence might boost their cause.

The demonstration will take the form of a huge "v" in the north of Barcelona, where two major thoroughfares converge. The v stands for via, vote and voluntat (will), though implicitly for victory, too. While victory may not be at hand, the separatists are gaining in confidence as their ranks continue to grow, helped by the obduracy of the Madrid government, which refuses to discuss the issue.

The Catalan government has called a referendum on independence for the region of 7 million people on 9 November. Madrid said the vote will be illegal.

Retired teacher Oriol Canals said: "The government treats the referendum as illegal and unconstitutional. It has subjected the independence movement to every kind of pressure, coercion and threats. As a result, the movement has grown by 20% in the past four years." Support for independence now stands at between 40-45%.

11 September marks the 300th anniversary of their loss of independence. Many eyes are now on Scotland and there is much talk about how the outcome of the referendum will influence the course of events here.

"There are many similarities, such as the uncertainties about the economy, the currency or whether we will belong to the European Union or Nato," said Larry Magrinyà, a Catalan who is married to a Scot. "On the other hand, Scotland enjoys greater recognition as a nation and it has, for example, its own football and rugby teams."

Magrinyà said that, while a yes vote would put wind in the separatists' sails, it would very likely make the Spanish government even more determined to prevent a similar outcome in Catalonia.

"The fact that the British government is allowing the referendum to go ahead shows that it is far more democratic than Spain," said Mar Carrera, a communications specialist. "An key difference with Scotland is here the independence movement is capitalising more effectively on social and cultural discontent.

"It's important to bear in mind that the Catalan independence movement is heterogeneous, ranging from members of the rightwing governing party to the far left."

The emergence of the pro-independence movement as a significant force took the political mainstream by surprise when close to 2 million people marched in Barcelona on this same date in 2012. It was grassroots pressure that forced the lukewarm nationalists who govern the country to call a referendum on 9 November on the right to decide.

"The main difference I see between the two is that the Catalan movement has been driven by social mobilisations, demonstrations and so on, often without the participation of political parties, which have tagged along later," said freelance photographer Joan Alvado. "From here it looks like there was much less activity in the street in Scotland and that Salmond's SNP has been the driving force."

Alvado said the impact of a yes vote in Scotland will depend on whether an independent Scotland is recognised by the international community. "If that happens, many Catalans will cease to be afraid of the possible consequences and reprisals that independence might bring."

It is by no means clear whether the vote will go ahead on 9 November. The Catalan president, Artur Mas, is a Christian democrat and loath to do anything illegal. At the same time, his party is in disarray after its totemic founder Jordi Pujol, who ruled Catalonia for 23 years, has confessed to a lifetime of large-scale tax evasion in an effort to keep two of his sons, who face corruption charges, out of jail.

Polls show Mas trailing the pro-independence Esquerra Republicana whose leader, Oriol Junqueras, has called for civil disobedience should Madrid try to block the referendum. He has not spelled out what he means by that but, in the absence of any dialogue between Barcelona and Madrid, there is a fear that things could turn nasty.