Many Russian accounts which went on a spree of tweets about Brexit were also strongly supportive of President Putin

Russian Twitter accounts posted more than 45,000 messages about Brexit in 48 hours during last year’s referendum in an apparently co-ordinated attempt to sow discord, The Times can reveal.

More than 150,000 accounts based in Russia, which had previously confined their posts to subjects such as the Ukrainian conflict, switched attention to Brexit in the days leading up to last year’s vote, according to research for an upcoming paper by data scientists at Swansea University and the University of California, Berkeley.

Russian activity spiked on June 23, the day of the referendum, and on June 24 when the result was announced. From posting fewer than 1,000 tweets a day before June 13, the accounts — many of which are virulently pro-Putin — posted 39,000 tweets