Ken McCallum, head of MI5, confirmed Tuesday that Russia attempted to interfere in the Brexit referendum through social media and television reports. McCallum stated the Kremlin's efforts had little impact on the outcome of the vote.
McCallum endorsed recent comments by Andy Burnham, who raised the issue over the preceding two days. However, McCallum cautioned that continuing to debate Russian interference risked providing the Kremlin with unnecessary propaganda advantage.
The MI5 chief did not detail the specific scope, timing, methods or scale of Russia's interference attempts beyond naming social media and television as channels used. He also provided no evidence of the claimed limited impact or explanation of how interference was assessed as ineffectual.
The confirmation comes as part of an apparent shift in official British acknowledgement of Russian electoral interference. Whether additional details about the interference campaign, its funding, coordination or objectives will be released remains unclear from the available information.