They do it differently over there.

About one million Catalan nationalists took to the streets of Barcelona on Tuesday to demand independence from Spain – that's about one-seventh of the entire population of the province. "Catalonia, new European state" they cried as the city was drowned in yellow and red – the colours of the Catalan flag.

It is hard to imagine anything like this happening in Scotland, even though support for full independence has been around the same level in both regions for much of the last 30 years. Scots just don't take to the streets on this issue, and the constitutional debate has been conducted here at an emotional level only marginally above somnambulism.

Yet, ironically, it is the Scottish independence referendum that has provided a catalyst for this eruption of Catalonian separatism. The demonstrators are demanding that there should be a legally binding referendum on Catalonian independence, just like Scotland's. But the central government in Madrid will not grant one on the grounds that there is no legal right of secession from the Spanish state. Spain fought a civil war partly over this 70 years ago, when Catalonia tried to secede from Francoist Spain.

Scottish Nationalists have been celebrating Catalonia's apparent conversion to independence, but they may not be cheering for long. The potentially chaotic break-up of Spain might discourage cautious Scots from seeking a similar course. Moreover, the crisis has apparently forced the European Union to change its guidance on the right of newly independent countries to remain in the EU. The senior spokesman for the European Commission, Olivier Bailly, declared on Tuesday that Scotland would be treated as a so-called "accession state", would have to leave the EU and then reapply.

It is important to examine the exact words he used. "There are two steps," said Mr Bailly in answer to a question about an independent Catalonia's status. "There is the secession process under international law and the request for accession to EU member state under EU treaties. In the meantime, of course, this new (country) is not part of the EU since it has to make a request for accession." The telephone lines between Brussels and the Scottish Government have been red hot ever since seeking "clarification".

The Nationalists say that, in the past, Jose Manuel Barroso, the President of the European Commission, has said only that there would need to be "negotiation" of the terms of Scottish membership of the EU, not that Scotland would – as it were – have to leave before it could rejoin. Unfortunately for them, Mr Barroso was asked directly about Scottish secession on the BBC's World at One programme yesterday and, while he said he would not speculate about possible secessions, he went on to say: "A new state, if it wants to join the European Union, has to apply to become a member like any state ... and the other states have to give their consent."

The SNP's argument is that since Scotland is already subject to EU law, membership should be automatic. This does not appear to be how the EU now sees it. The SNP has insisted also that, if Scotland were thrown out of the EU, England would be too. But the EU spokespeople do not appear to be saying that either, and seem to accept that the UK minus Scotland would still be a member state.

This is the first serious challenge faced by the new Scottish Cabinet Secretary with responsibility for the constitution, Nicola Sturgeon, and so far she has not stepped up to the plate. Her office was left yesterday rather lamely quoting the replies to Parliamentary questions asked in Europe about Scottish independence, and pointing out that none of them mentioned Scotland having to leave the EU before negotiations could commence. They also quote a raft of constitutional experts who say that a country already subject to EU law should "obviously" remain in the EU and that anyway there isn't a mechanism for secession from the EU.

Knowing the history of the European Union it would seem most unlikely that the EU would refuse entry to an independent country like Scotland. It has spent decades holding open the door to former eastern bloc countries such as Latvia, Estonia and Lithuania – so why would they not want Scotland to remain part of the club?

But they don't seem to be minded to give Scotland any right of automatic entry. Why is this? Presumably because the disintegration of Spain could make the eurozone debt crisis more difficult to resolve. This week the EU has been unveiling its plans for buying up the debt of countries like Spain. It doesn't want to have to deal with a lot of new accession states right now.

Catalonia is deep in debt and is shut out of the borrowing markets. It has been demanding 5 billion euros from Madrid to keep public services going, but Madrid says that, because of the EU bailout conditions, it can't meet these demands. This has infuriated Catalonian nationalists who insist that, since their province provides 20% of revenues with only 15% of the Spanish population, it should "get its money back". Catalonia has been running a kind of Barnett Formula in reverse subsidising – as nationalists see it – the rest of Spain.

British Unionists have had their best break for months now that the European Union appears to have blackballed an independent Scotland. Perhaps we can understand now why the Scottish Government has been so reluctant to admit whether or not it sought legal guidance from the Commission. It has actually taken the Scottish Information Commissioner to court over its right to non-disclosure.

This isn't good enough. Ms Sturgeon should abandon that action forthwith. The Scottish Government needs to get a grip on this issue. It should not be beyond the skills of the Scottish Government's lawyers to frame their "succession state" argument in a form which the EU would have to recognise. Why and how would an independent Scotland cease to be under EU jurisdiction? Why should Scotland be treated differently to the rest of the UK after independence? The EU has landed Ms Sturgeon in what the former US President George Bush called "deep doo doo". It's time to get her spade out.