The head of MI5 has rejected suggestions that Russia influenced the outcome of Britain’s 2016 Brexit referendum, drawing a distinction between attempts to interfere in the democratic process and evidence that such activity changed the result. Sir Ken McCallum’s intervention came amid a political dispute involving Prime Minister Sir Keir Starmer, Greater Manchester Mayor Andy Burnham and Conservative leader Kemi Badenoch over how to characterise Moscow’s involvement in the referendum.
Speaking at MI5’s Thames House headquarters in London on Tuesday, McCallum said it was important to distinguish between “interference attempted and outcome swayed”. He added: “The Brexit referendum result is not in dispute.” His remarks followed criticism of Burnham, who had been accused of implying that the referendum result was illegitimate because of Russian interference. Burnham denied making any such suggestion, insisting that he had always respected the outcome of the vote.
The dispute followed comments by Starmer on Monday, when he said it was important to put on record that Russia had interfered in the referendum. Speaking on The Rest Is Politics podcast, the Prime Minister said: “I asked the question coming to Downing Street: ‘Well, was there interference in the 2016 referendum from Russia?’ I’ve had the clear answer that, ‘yes, there was’.” The Government’s established position is that Russia attempted to interfere in the referendum but was unsuccessful in changing its outcome.
McCallum agreed with the Prime Minister’s assessment that Russian interference had occurred, while cautioning against overstating its effectiveness. He said activity by Russian media organisations, along with “trolls and bots”, had been detected during the referendum campaign and was a matter of public record. However, he expressed concern that prolonged political arguments about Moscow’s role could exaggerate the perceived power of Russian operations.
“I’m anxious that we don’t play into our adversaries’ hands by making these trolls look 10ft tall,” McCallum said, adding: “That is not our experience.” He warned that continued attention to the controversy would benefit those responsible for the activity. “They’ll be delighted because they are front page news once again,” he said.
The disagreement had already reached the House of Commons on Monday, when Badenoch accused Starmer of having “implied that the referendum result was illegitimate because of Russian interference”. Responding to the criticism, Burnham said he had implied “no such thing” and had “always respected” the referendum result. He also argued that Russian actors had sought to interfere in an earlier general election and said it was “inconceivable that this was the first time”.
McCallum said he agreed “strongly with what the Prime Minister said yesterday”, pointing to a “hack and leak” operation during the 2019 general election campaign. His comments did not alter the distinction he had drawn between evidence of attempted interference and evidence that an electoral outcome had been changed.
The Government is seeking to provide more information about Russian efforts to influence British public opinion. Luke Pollard, a defence minister, said on Tuesday that ministers wanted to be more transparent about a Russian campaign intended to “misinform and divide” the public. He said the Government believed Moscow had attempted to interfere in numerous British general elections but had so far been unsuccessful. At the same time, he warned that Russian efforts to intervene in and interfere with British democracy were increasing.
Asked whether the Government would publish evidence of such activity, Pollard pointed to the Ministry of Defence’s approach to explaining the Russian threat to the public. He said further disclosures could follow over the coming year, provided they did not compromise intelligence-gathering methods or endanger sources.
“I would expect in the coming year, as we move the national conversation around our defence and security as a nation into a new chapter, there will be further opportunities for us to reveal what Russia is doing [to interfere in our democracy] without putting any of the ways that we get that information in the public domain or any of those sources at risk,” he said.
The political dispute also intersects with Burnham’s position on Britain’s future relationship with the European Union. He is pressing for closer ties with the bloc and is expected to set out options following an EU summit on 20 November. Two weeks earlier, he had suggested that Labour’s next election manifesto could potentially include a commitment to hold another in-out referendum on EU membership or to rejoin the bloc without another vote.
Alex Burghart, the Conservative Party’s deputy leader, accused the Prime Minister of receiving an “extraordinary slap down” from the head of MI5. He also described Burnham’s response as an “embarrassing retreat” and accused him of questioning the referendum’s legitimacy to distract from other national issues.
McCallum’s remarks came during his annual assessment of security threats, in which he described Russia as the country’s principal state adversary. Russia “remains aggressor number one”, he said, citing hybrid warfare campaigns involving sabotage and cyber attacks. He added that MI5 was “devoting more resource to countering state threats than during the Cold War”.
The intelligence chief also warned that terrorists were plotting artificial intelligence-enabled drone attacks against Britain. Although the potential for AI to facilitate the development of new biological weapons had not yet materialised, he identified the possibility of creating “novel pathogens we have not previously seen” as a particularly serious concern. AI, he said, was “supercharging” the contest between attackers and defenders, while its potential to alter the threat posed by existing or new biological weapons remained the misuse scenario to which he attached the greatest weight.
