LONDON — Facebook and Twitter have promised to cooperate with another set of investigations into suspicions of Russian meddling in elections — this time in Britain, over the bitterly divisive referendum last year in which the country voted to leave the European Union.
More than 150,000 Russian-language Twitter accounts posted tens of thousands of messages in English urging support for withdrawal, known as Brexit, in the days before the June 23 vote, researchers have found, drawing parallels with Russian social media activity around the US presidential election later that year. Facebook has acknowledged that more than 126 million users may have seen inflammatory political ads bought by a Russian company, the Internet Research Agency, during the US campaign.
In a letter to the chairman of a British parliamentary committee, released Tuesday, Facebook promised to comply with a request for data “by the second week of December,” adding that its response would also be sent to the country’s official election watchdog, the Electoral Commission. Twitter made a similar promise to release material “in the coming weeks.”
Committee Chairman Damian Collins, a Conservative lawmaker who leads the House of Commons Digital, Culture, Media, and Sport Select Committee, had written to Facebook’s founder and chief executive, Mark Zuckerberg, requesting that the social network share material similar to that given to congressional committees investigating Russian election meddling in the United States.
Collins told the BBC that the committee was investigating whether there was “systematic distribution of false news by, particularly Russian-backed, organizations,” and that he hoped the release of the information would give British lawmakers “a better chance to understand the scale of Russian-backed operations during the referendum.”
“We have a right to know what was going on,” Collins said. “Some of the activity took place directly before the referendum and certainly during the campaign — that’s why I wrote to Mark Zuckerberg asking him that Facebook should give us the information about Russian-backed activity on their platform.”
Earlier this month, Britain’s prime minister, Theresa May, accused Russia of meddling in Western elections and planting fake stories in the media to “weaponize information” and sow discord. She did not make specific assertions in relation to British elections, however, or to the Brexit referendum, the outcome of which her government is in the process of implementing.
The “leave” side received 52 percent of ballots cast in the referendum, a winning margin of about 1.3 million votes.
Those inclined to suspect Russian interference in the campaign say that the EU’s economic sanctions on Russia for its intervention in Crimea — sanctions that Britain supports — may have given the Kremlin a strong interest in dividing the bloc.
An opposition lawmaker and former minister, Ben Bradshaw, called last month for a British government investigation into claims of Russian interference, adding that there were “questions” about Arron Banks, an insurance company owner and political gadfly who gave heavy financial backing to one of the campaign groups on the leave side.
That followed the publication of investigative reports into the financing of the campaign by the openDemocracy website, which included a detailed examination of Banks’ finances. No Russian link was proved, however, and Banks has dismissed the allegations.
In Facebook’s letter to Collins, Simon Milner, a policy director at the company, wrote that it had also been contacted “by the Electoral Commission’s head of regulation as they carry out their work looking at possible Russian interference in the Brexit referendum.”
“Given that your letter is about the same issue, we will share our response to the Electoral Commission with you,” Milner wrote.
Twitter’s response, by Nick Pickles, head of public policy for Twitter UK, similarly mentioned a request from the Electoral Commission. Pickles also argued that academic studies of potential disinformation campaigns on the social network “systematically underrepresent our enforcement actions,” for technical reasons.
The Electoral Commission said it was not conducting a specific inquiry into Russian involvement in the Brexit referendum but was looking for information on how the financing and use of social media during elections complied with British election law, which limits what campaigns can spend, and bans them from accepting most foreign donations.
It is investigating Banks’ donations, and whether Vote Leave, the official campaign to quit the bloc, circumvented spending limits.