Going, going... but not quite gone. Catalan leader Carles Puigdemont has stepped back from the brink of declaring independence and has instead asserted that he has the right to do so, while calling for talks on the future.

The barriers are that Spain's 1978 constitution renders the country indivisible, and that courts ruled that the referendum that look place was illegal. With the opposition parties and voters boycotting the vote, independence nonetheless took a share of the vote roughly equal to the total share achieved by Leave in the United Kingdom's EU referendum.

So it's likely, but not certain, that a referendum held with Madrid's blessing would have been won anyway. What is certain is that the Spanish government's aggressive policing and their heavy-handed attempts to stop the vote have boosted the chances of separation and gifted Catalonia international sympathy.

The differences between Catalonia and Scotland are so large as to render most comparisons otiose. But there is one useful take-home as the SNP conference draws to a close, and it's this: that regardless of what your constitution, written or unwritten, actually says, if the regional parliament wants to hold a referendum, it can hold one, with the only decision made by the national government an essentially tactical one.

Which means that if Brexit does end in tears and the balance of forces in Scotland shifts from No to Yes, no one should place any value on the constitutional right of the government in Westminster to refuse a referendum re-run.