Catalonia has much of the paraphernalia of statehood, but seceding from Spain as Britains Brexit process has shown wont be straightforward
The immediate practical consequences of Catalan independence like those of the UK crashing out of the EU without a deal would have far-reaching implications for the region, its businesses and its people.
As with warnings of City firms fleeing a hard Brexit, industry is already alarmed: half a dozen Spanish companies, including major banks, are moving their registered head offices to guarantee access to their domestic and wider EU markets.
Despite claims by pro-independence campaigners that the EU would not want to lose a wealthy region that would rank 15th or 16th in the bloc in terms of GDP, Brussels has made clear that the region will not automatically become a member.
It would have to apply, and acceptance would require the agreement of every other EU member state including Spain, which in 2014 threatened to veto an eventual Scottish accession bid precisely to discourage Catalan independence.