The head of Britain’s domestic intelligence service, MI5, has warned that Russia is intensifying its hybrid warfare campaign against European countries supporting Ukraine, raising concerns about sabotage, cyberattacks and other activities designed to undermine national security.
Speaking during his annual threat assessment on October 13, 2026, MI5 Director General Ken McCallum described Russia as the leading state threat facing Britain. He said Moscow was increasingly using tactics that fall short of conventional military conflict while seeking to intimidate the United Kingdom and its European allies. Hybrid warfare refers to a combination of methods that may include cyberattacks, sabotage, espionage, disinformation and covert operations. These activities can target critical infrastructure, public institutions and essential services without triggering an immediate conventional military response. McCallum said Russia’s military and intelligence services were escalating these tactics while attempting to remain below the threshold that could trigger NATO’s collective-defence response. He argued that the campaign was intended to unsettle European countries as Russia continues its war against Ukraine. Among the incidents highlighted were an attempted drone attack involving a cargo plane at a German airport and a cyberattack targeting Polish energy infrastructure. European authorities have increasingly raised concerns about suspicious activities affecting transport networks, defence industries and other critical facilities. McCallum also said Russia was increasingly relying on criminal networks and local recruits to carry out hostile activities. He linked this shift partly to the expulsion of nearly 1,000 Russian officials from diplomatic missions since the full-scale invasion of Ukraine in 2022, which has reduced Moscow’s traditional covert presence in Western countries. Russia denies involvement in hostile activities attributed to it by Britain and other European governments. The intelligence chief said state-related threats had quadrupled over the past decade. MI5 is now devoting more resources to countering threats from foreign states than it did during the Cold War, reflecting the growing importance of espionage, sabotage and other hostile activities in Britain’s national security planning. The warning comes as European governments strengthen cooperation on intelligence sharing, infrastructure protection and counter-sabotage measures. NATO members have also been reviewing their defence strategies in response to concerns about Russia’s military intentions and its activities below the threshold of open conflict.
McCallum urged organisations responsible for critical national infrastructure, including energy and defence facilities, to improve their preparedness against sabotage and cyber threats. He stressed that security measures should be implemented before an incident occurs rather than only after damage has been done. The MI5 chief also discussed threats from Iran, saying Tehran was expanding its efforts to target British interests, including potentially more sensitive sites such as military installations. He separately warned that terrorists could misuse artificial intelligence to develop more dangerous capabilities. For European governments, the growing challenge is to respond effectively to covert attacks while avoiding unnecessary escalation. Intelligence cooperation, stronger cyber defences and improved protection of essential infrastructure are expected to remain central to efforts to counter hybrid threats. McCallum’s warning highlights the increasingly complex security environment facing Britain and its allies. As Russia continues its war in Ukraine, Western intelligence agencies say vigilance and coordinated responses will be essential to protecting European infrastructure and national security.