Unrequited love rarely lasts long.

Catalunya's home rulers used to adore their supposed SNP allies - despite barely-disguised snubs from Edinburgh.

Just a few short months ago independentistas in Barcelona were rejoicing that Scotland would have a referendum, something, even now, they can only dream of.

Now they are despairing at the prospect of Scottish nationalists being hammered in the 2014 vote - and the possibility that a No landslide here could dent Yes sentiment in Catalunya.

This weekend Vilaweb - an influential pro-independence and left-leaning internet news site - began wondering why things were going wrong in Scotland.

Its conclusion: that Scotland's independence movement was "top down" while Catalunya's was "bottom up".

"In Scotland the process is practically exclusively led by the Scottish National Party, which is opposed by an ideologically diverse coalition," wrote the site's editor, veteran Catalan journalist Vicent Partal.

"In Catalunya, by contrast - and this became clear in the last elections - the people don't want a single party or a single leader to run the process. This is more complicated to manage - but it is also more robust.

"Unlike in Scotland, independentism in Catalunya rose from the grassroots and has pushed political parties, forcing them to take an increasingly clear position [on independence]."

Now the Yes Campaign in Scotland IS clearly wider than the SNP. But I am not sure even its firmest supporter would claim it has anything like the grassroots support seen in Catalunya.

Because Partal is quite right about how bottom up the independence movement is in his nation.

Traditional Catalanist leaders - such as current conservative president Artur Mas - have moved closer and closer to support for full-fat independence since mass ralles in September of 2012.

Quite exactly what Mas means by "independence" is still to be seen. But more than 70% of the population of Catalunya, according to the latest poll, wants to see it come about. Compare that with around a third of Scots who support the admittedly more clearly defined independence on offer here.

Hence the Vilaweb editorial. Support for the SNP in any Holyrood poll is higher than support for independence. No Catalanist party, including the SNP's formal allies Esquerra, can command the kind of electoral support enjoyed by independence itself.

"In Scotland the nationalists will have to work hard if they want to win the referendum, which looks like it is going to be very difficult," Partal concluded.

"This provokes two thoughts. First: it would be better if we hold our referendum before theirs. Second, the time has come - without false modesty - to say our campaign so far has been successful."

Catalans have a slight problem with Scotland's referendum. They can make political capital out of the fact it is taking place at all. And they can lose capital because of its most likely outcome.

Hence Portal's conclusion - shared by several independentistas I have spoken to over the last few months - that any Catalan vote should take place no later than the Scottish one.

That, of course, will be tricky - given Madrid's opposition to such a move. But not impossible.

Catalans - and other would-be breakaway groups in Europe - frequently cite the Scottish referendum to back their case.

Usually, however, they praise David Cameron rather than the SNP.

(Catalan nationalists can see British unionists as cuddly democrats but Spanish ones as Franquista brutes, relics of the 1939-75 dictatorship.

Partal argues that Madrid's aggression helps boost his cause, while what he see as a more reasonable approach from London hampers the Scottish movement.)

SNP leaders, meanwhile, have made it clear they want to stay out of Spanish politics. They didn't congratulate Mas and his CiU alliance on their election victory in November. They didn't even praise their formal allies in Barcelona, left-wing nationalist party Esquerra, when it gained seats.

Instead, as The Herald revealed at the time, the party issued a terse statement saying the elections were "a matter for the people of Catalonia".

High-level links between the SNP and both CiU and Esquerra seem to be on hold - although it is only in the last few weeks that Catalan nationalist news sources have figured this out.

Reports have suggested Catalan officials feel "betrayed" by Salmond. Maybe. But my guess is they are more worried by what is happening in the Scottish polls than by the lack of fraternal visits from SNP politicians.

Lots of rank-and-file Scottish nationalists, meanwhile, feel genuine affection for Catalunya. Is this still reciprocated? I am sure it is. But do Scottish nationalists have what it takes to right the wrongs perceived by Partal? Let me know what you think.