Britain has been warned to prepare for possible Russian retaliation after Prime Minister Andy Burnham’s visit to Ukraine and the UK’s decision to share technology that could help Kyiv produce long-range missiles.Security sources cited by the Daily Mail have warned that Russia could mount a “direct response” against Britain, amid concerns in Whitehall that Moscow may have underestimated Burnham’s commitment to Ukraine.A senior source told the newspaper: “The question being asked is, “How long do we keep poking the bear before it bites?””The warning comes after Britain agreed to hand Ukraine blueprints for British-made components used in the Storm Shadow cruise missile, allowing Kyiv to produce the long-range weapon domestically.Russia has reacted angrily to the move, with Kremlin spokesman Dmitry Peskov saying on Monday that Britain’s involvement prevented “even the slightest progress” towards peace.Peskov also said the Russian military was gathering information on missile production sites in an apparent warning that such facilities could become targets.“Britain is involved in this war on the side of the Kyiv regime. Britain methodically and regularly adds fuel to the fire,” he said.Burnham hit back during his visit to Ukraine, asking: “Who started the fire? That’s the question, isn’t it?”His trip to Kyiv was his first official international visit as prime minister, where he met Ukrainian President Volodymyr Zelensky and chaired a meeting of the “coalition of the willing”, established by Britain and France to support Ukraine.The warnings of possible Russian action were reinforced by comments from former Russian deputy foreign minister Andrei Fedorov, who suggested Moscow could consider a “semi-military” response.Speaking to BBC Newsnight, Fedorov said there was pressure on Russian President Vladimir Putin “to undertake certain measures against UK”.Asked what such a response could involve, he said: “It could take the form of something might happen with enterprises, with factories which are producing drones for Ukraine.”“They could be attacked not by Russia, but by from unknown sources.”The comments come as Russia itself faces growing pressure from Ukrainian drone strikes, particularly against oil refineries and other critical infrastructure.President Vladimir Putin has issued a decree allowing the Russian state to temporarily take control of critical infrastructure if private owners fail to adequately protect facilities from Ukrainian drone attacks or rebuild damaged sites.The measure covers energy, industrial, communications, transport and logistics facilities, with Kremlin officials insisting it does not amount to widespread nationalisation.Kremlin spokesman Dmitry Peskov said businesses were often failing to pay sufficient attention to “anti-drone safety”, while Putin has called for stronger coordination between the military, security agencies and private companies.Ukraine has continued targeting Russian energy infrastructure, with its General Staff reporting strikes on the Afipsky and Novoshakhtinsk oil refineries.Burnham has nevertheless reaffirmed Britain’s support for Kyiv and said he plans to travel to the US next month with European leaders to press President Donald Trump on Ukraine’s defence needs.