The UK is at a "moment of consequence" as Russia is "relentlessly targeting" critical infrastructure, the UK's largest spy agency will warn.
GCHQ Director Anne Keast-Butler will set out threats facing the UK and the measures she believes need to be taken to confront them when she makes her inaugural public speech on Wednesday.
In excerpts from her address, Keast-Butler singles out Russia for "targeting critical infrastructure, democratic processes, supply chains and public trust".
Russia has been blamed for a string of espionage plots on British soil and, more recently, waging an undeclared 'hybrid war' against the UK and other Nato countries. The Kremlin has denied the allegations.
Keast-Butler says GCHQ is working tirelessly to fend off cyber attacks and counter what she calls "reckless sabotage and assassination attempts".
She adds that: "In the face of such aggression and chaos, GCHQ is working tirelessly with intelligence and Defence partners to degrade and reduce the Russian threat."
The Kremlin, which denies responsibility, has been blamed for the murder of former KGB officer Alexander Litvinenko using radioactive Polonium slipped into his tea in a London hotel in 2006.
It was also blamed for the attempted assassination of a former Russian military intelligence officer, Sergei Skripal, in Salisbury in 2018, using the lethal nerve agent Novichok smeared onto his front door handle.
More recently, since Russia's full-scale invasion of Ukraine in 2022 and the UK's ongoing support for Ukraine, Moscow has been accused of waging a "hybrid war" against Western countries.
In her speech, the GCHQ boss is expected to say: "As we remain steadfast in our support for Ukraine, Putin is going backwards on the battlefield."
Hundreds of so-called Russian "shadow fleet" vessels have also entered UK waters since the prime minister threatened to intercept them earlier this year, a BBC Verify analysis suggested.
China, she will say, is now a science and tech superpower with sophisticated capabilities "across their intelligence, cyber and military agencies".
When it comes to global advances in AI and technology, she says, there is a narrowing window for the UK and its allies to stay ahead. She characterises it as "the ground beneath our feet" shifting.
She sees collaboration with the tech industry, academia and even the public as key to staying abreast of advances in cyber security.
GCHQ spends much of its time combating organised criminal networks bent on targeting vulnerable British firms with phishing attacks and ransomware.
Adopting the phrase "from boardrooms to living rooms", Keast-Butler urges everyone to look to their own cyber security
"At home that means taking important action now to switch passwords for passkeys, and for wider society, it means hard-wiring security into new technologies, protecting supply chains and making cyber security 10 times more urgent," she will say.
The address is due to be delivered from Bletchley Park, the agency's original wartime home.
GCHQ – short for Government Communications Headquarters – is the largest of the UK's three spy agencies, the others being the Security Service (MI5) and the Secret Intelligence Service (MI6).
Based in Cheltenham and housed in a huge, circular building known as the Doughnut, GCHQ focuses on cyber security and signals intelligence.
With its focus on cutting-edge technology, it consumes the lion's share of the national intelligence budget.
