Russia has lost 500,000 soldiers since it began its full-scale invasion of Ukraine in 2022, the UK’s intelligence chief said in London.
GCHQ director Anne Keast-Butler gave the latest figure for Russian casualties in Ukraine during her first public speech at Bletchley Park, saying it proved Vladimir Putin was “going backwards in the battlefield”.
Ms Keast-Butler warned Russia was risking a wider conflict in Europe by targeting critical infrastructure and supply chains across the continent.
She also said Russian security services were behind espionage plots in multiple countries and blamed Moscow for “scaling up its daily hybrid activity against the UK and Europe”.
Assessments by Western intelligence and independent analysts suggest both Russia and Ukraine have seen hundreds of thousands of troops killed in the war, with Moscow’s losses likely significantly higher than Kyiv’s.
Neither side publishes regular figures on its own casualties, and both accuse each other of exaggerating their enemy’s losses.
An estimate by exiled Russian media outlets Meduza and Mediazona recently suggested that close to 352,000 Russian soldiers had been killed as of the end of 2025.
In February, Ukraine’s president Volodymyr Zelensky said Ukraine has lost 55,000 soldiers on the battlefield.
Russia has not released figures on its battlefield deaths since January 2023, when it said more than 80 soldiers were killed in a Ukrainian strike, bringing the total military deaths Moscow has confirmed to just over 6,000.
Elsewhere in her address, Ms Keast-Butler warned that artificial intelligence was emerging as “an unstoppable force” that was being weaponised in ways that fall just short of traditional warfare.
“I’ve spent three decades working in national security. And the risk of miscalculation is as high as I’ve ever seen it,” she said in her speech at the historic Second World War code-breaking centre near London.
“Tech companies are releasing AI-driven innovations at a remarkable pace, with untold consequences, as algorithms are weaponised often just below the threshold of traditional warfare,” she said.
She singled out Russia for “relentlessly targeting critical infrastructure, democratic processes, supply chains and public trust” in Britain and Europe.
Russia and China have been investing in this space, for both military and other purposes, she said, adding that they have been working to fend off cyberattacks as well as “reckless sabotage and assassination attempts”.
