UK says nearly 500,000 Russian troops killed in Ukraine

The Director of GCHQ has warned that the risk of miscalculation between states is as high as she has seen across three decades in national security, telling an audience at Bletchley Park that the world now occupies “a space between peace and war”.

Anne Keast-Butler delivered the agency’s first Annual Lecture in the Fellowship Auditorium at Bletchley Park on Wednesday 27 May, the wartime home where British codebreakers worked during the Second World War. She noted that it is rare for the head of an intelligence agency to speak in public, framing the decision to do so as a response to what she described as a moment of consequence. “The risk of miscalculation is as high as I’ve ever seen it,” she said, pointing to an era of radical uncertainty, contested geopolitics and rapidly changing technology.

On Ukraine, Keast-Butler said new intelligence indicates almost half a million Russian soldiers have been killed since the start of the conflict, and that President Putin is “going backwards on the battlefield” as Britain maintains its support for Kyiv. The figure came as she set out a section on Russia, which she said is scaling up daily hybrid activity against the UK and Europe across a range from the seabed to cyberspace, targeting critical infrastructure, democratic processes, supply chains and public trust. She said GCHQ is working with intelligence and defence partners to degrade that threat, including by exposing Russian intent and underwater capabilities around British waters and by disrupting attempts to smuggle Western technology.

Much of the address centred on the pace of technological change. Keast-Butler said warfare is being reconfigured and becoming more data-driven, AI-enabled and automated, pointing to conflicts from Ukraine to Iran, and described China as a tech superpower with sophisticated cyber, intelligence and military capabilities. “Technology and data are no longer just tools; they are transformational forces,” she said, characterising data as a strategic asset whose value grows when paired with artificial intelligence. “Data is the lifeblood of our society, our economy, and our warfighting capability,” she added.

On cyber security, she pressed businesses to act without delay. “Cyber security is a critical priority for all businesses,” she said, adding that GCHQ experts are producing large volumes of advice but that “we need businesses to take immediate action now.” She described the security environment in stark terms, telling the audience that “the ground beneath our feet is shifting, and shifting fast.” According to the agency, GCHQ has developed over recent months a blueprint for a new national cyber defence capability intended to build agentic AI into machine-speed cyber defence.

Quantum technology featured prominently. Keast-Butler, a mathematician by background, said the timeline she had long assumed for operationalising quantum had shifted. According to the agency, quantum sensing is already in use, with work alongside academia and industry aimed at identifying the signatures of stealth, including the detection of missile launches. She warned that “once they are operational, quantum computers will be able to complete, in a matter of seconds, tasks that currently take years” — including defeating the encryption that protects today’s secrets — and repeated a call for businesses to migrate critical systems in line with timelines set by the National Cyber Security Centre.

She also addressed technology sovereignty, arguing it concerns the agency, ability and agility of nations to shape their own digital future rather than a requirement that everything be made domestically. “Sovereignty doesn’t have to mean ‘made in the UK’, so long as we carefully manage our supply chains, dependencies, and data,” she said. She traced GCHQ’s pioneering of public key cryptography in the 1970s, noting that the same mathematics secures online commerce, keeps fighter jets in the air and protects the nuclear deterrent.

Partnerships ran through the speech as a recurring theme, drawing on the example of Alastair Denniston, the first Director of GCHQ. She marked the 80th anniversary of the UKUSA intelligence-sharing partnership with the United States National Security Agency, described the Five Eyes as the agency’s most critical partnership and the one most feared by adversaries, and said strategic intelligence relationships with European partners continue to deepen, strengthening NATO. Drawing a contrast with Britain’s adversaries, whose partnerships she said intelligence shows to be strained and transactional, she put it plainly: “Our adversaries don’t do teamwork – we do.”