I found a Channel 4 piece from November last year, discussing 3 papers, roughly in the order of the quantity of evidence (which however might be inversely correlated with the certainty that they were an organized effort--a fair point raised in a comment below):
This week, further research into Twitter bots and the Brexit vote was published by the Oxford Internet Institute. It looked at 22.6 million tweets and cross-referred them with 2,752 accounts that the US Senate has identified as creations of the Russian Internet Research Agency.
Researcher Yin Yin Lu told Sky News that she had found 416 tweets from the Russian accounts from March to July 2016 (i.e. the months preceding the EU referendum).
She was careful to point out that “the number of these tweets is important to highlight. So there’s about 400 tweets here out of 22.6 million. That is a very infinitesimal fraction. So the word ‘interference’ is perhaps a bit exaggerated”.
Although she did say that the tweets did appear to be coordinated – with accounts apparently retweeting and sharing each other’s content. She said “there’s some kind of network happening here”.
A second report – this time from the University of Edinburgh – found a higher number of tweets about Brexit from the Russian Internet Research Agency. The Guardian reports that researchers identified 419 accounts operating from the Agency that were attempting to influence UK politics. The accounts were on the list of 2,752 accounts suspended by Twitter in the US.
Professor Laura Cram, who led the research, told the Guardian that those 419 accounts tweeted about Brexit at total of 3,468 times – mostly after the referendum had taken place.
Separately, an upcoming paper from researchers at the University of California, Berkeley, and Swansea University is set to reveal an even wider network of pro-Brexit Russian bots.
The research – which has been seen by the Times newspaper – tracked over 150,000 Russian accounts that used the hashtag “Brexit”, most of which were advocating Britain’s departure from the EU.
One account, “Svetal1972”, posted 92 tweets between 20 and 24 June, including one that called for Britain to “make June the 23rd our Independence Day”.
So there’s some evidence of Russian involvement in spreading pro-Leave sentiment online – although nothing as yet that suggests interference on the same scale as is alleged in the US.
The article then goes on to dissect what might have been the Russia's reasons for trying to influence Brexit.
What I want to ask here: has there been more evidence of Russian involvement in Brexit since that article was published?