Veterans from Scotland's failed bid for independence in its own referendum in 2014 said they were travelling to Barcelona next week to offer their support for a vote deemed unconstitutional by Spain.
"We back the Catalans," Rory Steel, vice convenor of the Scottish National Party's youth wing, who will be heading out with around 20 people, told AFP.
"We're basically going over to find out a bit more about them, trade our experiences and expertise and that sort of thing, but also to support them."
Another delegation of politicians and writers is also planning to head over for the October 1st vote as observers, after a crackdown on the team organising the referendum and mass protests.
Scottish First Minister Nicola Sturgeon, head of the Scottish National Party, voiced her concern about the situation and called for dialogue in a debate in Scotland's semi-autonomous parliament last week.
"The right of self-determination is an important international principle and I hope very much that it will be respected," said Sturgeon, calling for an agreement based on the deal that led to Scotland's own independence referendum in 2014.
'We are Catalans'
The support is coming not only from nationalists.
An open letter to Spanish Prime Mariano Rajoy calling his actions "in no way democratic" received support from more than a dozen Scottish lawmakers including some opposed to Scottish independence.
Scotland's referendum vote was won 55 percent to 45 percent by those who wanted to stay part of Britain.
But Sturgeon has said that Scotland, which voted overwhelmingly to stay in the European Union in last year's referendum on EU membership, should have a right to vote again once the terms of a Brexit deal become clear.
Former SNP MP George Kerevan, who founded the All Party Parliamentary Group on Catalonia, said: "The worst thing that we could do now is let that regime in Madrid crush Catalan democracy.
"If you believe in a Scottish democracy, if you believe in a Scottish right to vote, then you have to defend Catalonia's right to vote. We are Catalans and Catalans are Scottish," he said.
There is a long-running affinity between Scottish and Catalan separatists.
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In the Scottish referendum, a group of Catalan firefighters came to Scotland to lend their support to the independence movement in a convoy including a vintage car painted in the colours of Catalan flag.
Last year, Barcelona fans threatened to fly the Scotland flag at the Copa Del Rey final in Madrid after the government banned the Catalan flag, until the prohibition was overturned in court.
However, the SNP leadership kept Catalan separatists at arms length during their own referendum, as they sought to present Scottish independence as unique and prevent any international interference.
Precedent for Scotland?
The contrast between the Scottish and Catalan referendums could not be more stark.
London permitted Scotland's referendum to go ahead after a nationalist landslide in elections to the Scottish Parliament in 2011, and the campaign was widely regarded on both sides of the debate as a model of democratic engagement.
There were just a handful of arrests, mostly for minor disorder such as egg throwing and online abuse.
The detention of organisers and seizure of campaign material in Catalonia have shocked Scotland.
Some in Scotland fear that if Madrid successfully suppresses the Catalan vote, it could set a precedent for London, which has refused to allow a re-run in Scotland in the near future.
Jonathon Shafi, founder of Scotland's Radical Independence Campaign, said: "It is not beyond the realms of possibility that the British state might do the same thing years down the line if Scotland looks like it is going to move toward independence.
"If we allow the Spanish state to set the precedent that this type of anti-democratic practice can take place, then it is a precedent that is not just set for Spain, it's set for the United Kingdom and indeed beyond.
"This is a question for the whole of Europe -- and it's a question for democrats everywhere."
By Mark Mclaughin / AFP