Beyond the confines of Britain, the prospect of an independent Scotland has produced a mixture of confusion, astonishment, glee and horror.

India's foreign minister, Sushma Swaraj, looked baffled when asked to comment on the possible break-up of the United Kingdom . "Break-up of the United Kingdom? I don't think there is any possibility of that. God forbid!" she said, before a whispered aside from an aide prompted another terse but bewildered line. "It's for Scotland to decide, I have nothing to say on this."

Catalans have seized on the spotlight being shone on Scotland to highlight the differences in how the desire for independence is being received in London and Madrid. "Our wishes in Catalonia must be respected, just as the UK government has respected those of Scotland," Barcelona mayor Xavier Trias said.

Spanish prime minister Mariano Rajoy has repeatedly said that any type of regional consultation on independence, binding or not, would be illegal. In the coming months, Rajoy's view is widely expected to be backed by Spain's constitutional court.

The contrast has turned Scotland and David Cameron into unlikely heroes in Catalonia. As hundreds of thousands of Catalans formed a V in the streets of Barcelona on Thursday to demand a referendum on independence, the sea of red and yellow Catalan flags was dotted with a handful of Scottish flags. Cameron "will go down in history as a leader who respected democracy," Mas told reporters, adding: "We admire the quality of their democratic system."

One country that has been nervously watching the yes campaign gather momentum is China, which has fought for decades to suppress separatist sentiment in Tibet and neighbouring Xinjiang province, home to the Uighur minority group. China's restive west, like Scotland, is relatively sparsely populated but accounts for a significant portion of the country's territory and has reserves of oil and gas. Scottish independence would be an uncomfortable fact on the ground for Chinese leaders.

Beijing's official line is a bland endorsement of Scotland's right to decide its future. Shi Yinhong, professor of international relations at Renmin University of China in Beijing, said the move would no more set a precedent than the recent division of Sudan into two nations. Still, he admitted he was hoping for a no vote. "I personally think that my government and myself do not support independence; we are used to Great Britain," Shi said. "I don't think the major adjustment to a new situation is anything that the Chinese government would want."

On a visit to London earlier this year prime minister Li Keqiang had called for a "strong, prosperous and united United Kingdom" when asked about the referendum, and some nationalist voices are far blunter.

Last week a populist, state-run tabloid warned the government a break-up would turn the UK into a "second-rate" country. Cameron would go down as "a sinner of history", the Global Times thundered.

In Russia, nationalists are thrilled at the possible dissolution of a meddlesome enemy and the apparent humiliation of London. First minister Alex Salmond's professed admiration for "certain aspects" of Putin's politics may also have bolstered support.

Public backing came from figures such as hardline politician Konstantin Rykov, who changed his name on Twitter to "McRykov" and put a yes in blue and white over his profile picture. Like many others he seems gleeful that the Scottish referendum comes as rebels in eastern Ukraine fight to throw off Kiev, drawing parallels between Scottish voters and the rebel fighters backed by Russian military expertise and hardware. Among the referendum news and pictures dotted through his feed is a mock-up of rebel commander Igor Girkin in a kilt, captioned only "Igor Ivanovitch McGirkin". Russia's own military suppression of separatists in Chechnya Dagestan gets no mention.

In the Middle East the vote is being followed closely by Kurds fighting for an independent state and inspired by the momentum of the yes campaign. "It's just one week away from the poll and the British are exercising the old colonialist tongue to control the minds and dampen the aspirations of Scottish people who want to vote yes," the Kurdistan Tribune warned in an editorial.

But otherwise it has largely been ignored. In Egypt, conspiracy theories about western attempts to divide the country are popular, but few people have noticed that the UK could be on the brink of its own democratic split. "The only news from UK making headlines in Egypt is Prince Harry's potential Egyptian girlfriend," said Zeinobia, one of Egypt's highest-profile bloggers.

Additional reporting by Patrick Kingsley in Cairo, Tania Branigan in Beijing and Ashifa Kassam in Madrid