The SNP has warned it would 'naive' to assume Russia was not meddling in Scotland after it emerged pro-Kremlin internet trolls fuelled claims the independence referendum was rigged.

Experts have long regarded fake news of irregularities in the 2014 vote – first made by a Moscow-based state news agency - as a textbook example of Russian attempts to destabilise the West.

Now researchers have uncovered a huge push by social media accounts which usually support Vladimir Putin to share videos and links amplifying the inaccurate Scottish stories.

SNP MP Stewart McDonald - a regular critic of Russian propaganda - said: "We know that the government of Russia is engaged in a campaign of undermining confidence in, and the stability of, democratic institutions and instruments around the world.

"It would be naive to think that Scotland was immune from this."

Mr McDonald was backed by the former chief executive of Yes Scotland, Blair Jenkins, who urged independence supporters to use "caution" on anything from anonymous social media postings.

He said: "People need to be careful with what they encounter on Twitter. You just don't know what might be behind it."

Internet watchers from the Atlantic Council’s Digital Forensic Research Lab linked the campaign to cast doubt on the independence referendum with the a later drive by the Russian government to use social media to back Donald Trump‘s presidential candidacy.

Ben Nimmo, a defence and international security analyst for the US think-tank, said “pro-Kremlin accounts demonstrably boosted” allegations of fraud following 2014's vote.

He called for ongoing investigations into Russian interference in last year’s EU referendum and US election should be widened to cover events in Scotland.

Analysts know accounts with strongly pro-Putin views supported the vote rigging allegations but have no way of knowing whether these accounts were working directly for the Kremlin.

Mr Nimmo said: “Pro-Russian internet trolls fuelled claims that Scotland’s independence referendum in 2014 was rigged, and amplified demands for a re-vote.

“The behaviour of these accounts is pro-Kremlin, and consistent with the behaviour of accounts know to be run by the so-called “troll factory” in St. Petersburg, Russia, during the United States 2016 presidential election.

"However, it is not possible to determine from open sources whether some or all of the accounts are independent actors, or linked to Russian information operations.

"Given the concerns expressed in the United Kingdom over the support of Russian trolls for Brexit, and in the US over Russian interference in the 2016 election, much more research is needed into the activity of pro-Kremlin trolls around Scottish independence, and much more investment is needed into building Britain’s resilience against online disinformation.”

He added: “The allegations of fraud demonstrably had an impact; pro-Kremlin accounts demonstrably boosted those allegations.

“The anger and disappointment felt by many Yes voters were entirely sincere, and are not the subject of this analysis; however, those sentiments were fanned by pro-Kremlin trolls, in a manner characteristic of Russian influence operations.”

Academics have previously uncovered evidence that tens of thousands of Russian accounts tweeted about Brexit in the run up to last year’s referendum.

This week US analysts noted that Russian twitter accounts - including official ones of of state media organs - were promoting the hardline pro-Trump Republican Ron Moore in the bitter Alabama senate race.

Experts have long stressed that Russian propaganda channels and pro-Russian accounts seek to amplify existing anti-establishment messages almost regardless of their content.

Russia even backed rival left and right groups in Germany during this year's elections.

Mr Nimmo’s analysis for the Atlantic Council – which is linked to NATO – found there was significant substantial evidence that videos purporting to show fraud during the Scottish independence referendum had been created by Russians.

One showed footage of ballot rigging in Russia in 2012 – wrongly claiming the images were from Scotland.

The videos were promoted extensively by Russian social media accounts and bloggers, with the claims then sparking petitions demanding a rerun of the referendum – which in turn were shared by pro-Russian accounts.

Mr Nimmo said he was suspicious about where many of the signatures on one particular petition, which garnered more than 100,000 supporters, had come from.

No evidence of fraud was found at any of Scotland’s referendum counts, and the SNP leadership has previously rejected the allegations.

Claims of rigging were first made by Russian election observers and then reported on RIA Novosti, a state-owned news agency and precursor body of Sputnik, the propaganda internet publisher and radio station which has an office in Edinburgh.

The SNP has boycotted Sputnik and its sister organisation RT, despite several parliamentarians appearing on the the channels.

However, former First Minister Alex Salmond, who recognised the No victory in 2014, recently began a weekly chat show on RT. A spokesman for current First Minister Nicola Sturgeon made it clear no Scottish ministers would appear on the programme.

Mr McDonald said he was still to review the new evidence of Russian trolling on the independence referendum but had discussed the general issue with academics at Edinburgh University investigating the wider issue.

Mr Jenkins of Yes Scotland said he felt that abrasive social media postings during the independence campaign failed to "capture the public mood".

He said: "I was on the road for two years and people had very strong views on either side but my experience was that the debate was always courteous."