Confirmation of a hack by a Chinese state group would be awkward for the government ahead of a planned visit to Beijing next year by Sir Keir Starmer, the first by a UK prime minister since 2018.
The Labour government has said it is important to engage with China as it cannot be ignored on trade, climate change and other major issues, but face-to-face meetings also provide a forum for robust exchanges about issues affecting UK security.
The Chinese government has consistently denied it backs cyber-attacks targeting the UK.
Last year, responding to the UK government’s National Security Strategy, a spokesperson for the Chinese embassy in London said “accusations such as Chinese espionage, cyber-attacks, and transnational repression against the UK are entirely fabricated, malicious slander”.
Earlier this month, Sir Keir said UK government policy towards China could not continue to blow “hot and cold”.
Failing to navigate a relationship with China, he said, would be a “dereliction of duty” when China is a “defining force in technology, trade and global governance”.
Building a careful relationship would instead bolster the UK’s place as a leader on the international stage and help secure UK national interests, Sir Keir said, while still recognising the “reality” that China “poses national security threats”.