On Monday, Sunak said Britain was facing a threat from "an axis of authoritarian states like Russia, Iran, North Korea, and China", and those warnings were echoed by GCHQ’s Anne Keast-Butler.
"As the prime minister said yesterday, the next few years will be some of the most dangerous and transformational," she told a security conference in Birmingham, central England.
In her first major public speech since being appointed director of the intelligence communications agency last year, Keast-Butler said the threat from Russia was acute and globally pervasive, with concern about growing links between the Russian intelligence services and proxy groups.
Iran remained aggressive in cyberspace, and groups associated with Tehran have been implicated in attacks against victims in many countries.
But she said China was her agency’s top priority.
"In cyberspace, we believe that the PRC’s (People’s Republic of China) irresponsible actions weaken the security of the internet for all," she said.
U.S. National Cyber Director Harry Koker told the conference Chinese military hackers were circumventing U.S. defences in cyberspace and targeting U.S. interests at an "unprecedented scale".
"In a crisis or conflict scenario, China could use their pre-positioned cyber capabilities to wreak havoc in civilian infrastructure and deter U.S. military action," he said.
