A political row is brewing after Labour warned of a "Conservative Party, establishment cover-up" over an anti-disinformation think tank accused of political attacks against senior Labour figures.
The Institute for Statecraft, which has received £2.25 million in Foreign Office funds, was accused of using public money to pursue an "infowar" against Labour.
A report in the Scottish Sunday Mail found the London-based think tank had sent a number of political tweets, several of which criticised Labour's relationship with Russia.
The Institute for Statecraft claimed it was the victim of a disinformation campaign – and this afternoon, the Foreign Office concurred, telling Sky News: "The Institute for Statecraft, an independent charity, was hacked several weeks ago and numerous documents were published and amplified by Kremlin news channels.
"This is yet another example of Russian disinformation intended to confuse audiences and discredit an organisation which is working independently to tackle the threat of disinformation."
Labour, whose shadow Foreign Secretary, Emily Thornberry, had earlier described the tweets as "simply outrageous" and a "smear", disagreed.
"This isn't about Russia," shadow Justice Minister Richard Burgon told Sky News. "This isn't about anything other than our concern that the Conservative government in this country shouldn't be using public funds or the state to undermine or attack the official opposition.
"That's why we're calling for a full enquiry, an independent enquiry. We can't have a Conservative Party, establishment cover up. We need to know the full facts."
The Foreign Office statement confirmed, almost in its entirety, the account of the Institute for Statecraft. Senior Fellow Stephen Dalziel told Sky News that his organisation had been the victim of "a classic Russian disinformation ploy".
Mr Dalziel explained that the Institute for Statecraft had been hacked three weeks ago by unknown hackers, who stole internal documents, including names of Foreign Office-funded projects and lists of friendly journalists.
Russian state broadcaster RT claimed this project – which went under the name of the Integrity Initiative – was gathering opinion leaders to foment anti-Russian sentiment, citing the stolen documents, which it claimed had been provided to it by "Anonymous" hackers.
Mr Dalziel said IT experts were investigating the hack, but he suspected it came from Russia.
"It's entirely possible that Russia was behind [the hack]," he said, "given the speed with which Russian media picked up on it, starting retweeting it, started broadcasting about it, [but] we have no solid evidence at the moment."
Mr Dalziel said the Institute for Statecraft had hired "IT people" to investigate the hack and that he was "looking forward" to writing a paper on it.
He criticised the Sunday Mail for its reporting, which described tweets calling Labour leader Jeremy Corbyn "a useful idiot" as an "infowars attack", and linked the fact that the Institute for Statecraft's registered address was a derelict mill in Fife to operations it described as "shadowy" and "secret".
"Unwittingly perhaps, they are being played by Russia because certainly there are no 'black ops' from the Integrity Initiative, we are very open about what we do.
"We have created a network of people across Europe who understand the problem of disinformation and malign influence, much of it from Russia.
"We haven't hidden that. We speak at conferences. We publish on our website. We have a very active Twitter feed."
The site in Fife, Mr Dalziel said, belonged to one of the organisation's founders, Dan Lafayeedney. It had been a working office before the organisation moved to London, but had been left as the registered address, an "oversight" the charity planned to correct.
Mr Dalziel stressed that the Institute for Statecraft's Twitter account, which he did not run, had also criticised Conservative Party politicians. He did not apologise for its contents, saying he would see if there was anything that demanded an apology.
Asked if the Institute for Statecraft was considering legal action against the Sunday Mail, Mr Dalziel said he was "speaking to lawyers".
Brendan McGinty, editor of the Sunday Mail, told Sky News: "We were made aware of claims that a Foreign Office funded organisation, Integrity Initiative, had carried attacks on the Labour leader Jeremy Corbyn on its Twitter feed.
"The Sunday Mail established that this was indeed true. We duly published a story which is clearly in the public interest. The Foreign Office quickly announced their own investigation.
Any suggestion that we are party to a campaign of misinformation is a vituperative smear. There is no misinformation. As yet nobody has found significant inaccuracy in our report.
"Indeed it has resulted in concern being expressed by respected journalists and politicians.
"Criticism of the report has taken two forms: one to accuse the Sunday Mail of being party to spreading misinformation; the second claiming that Integrity Initiative have also criticised a Conservative politician (a single member of the House of Lords who does not rely on election).
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"The first is clearly inaccurate, the second irrelevant.
"It is concerning that Integrity Initiative and Statecraft would choose to respond in the way they have. As a newspaper we continue to investigate."