UK Prime Minister Rishi Sunak expressed his significant concerns to Chinese premier Li Qiang about China's interference in democracy, following the arrest of a parliamentary researcher for spying. The arrest was made by UK police, who apprehended a man in his twenties, believed to be a researcher in Britain's parliament.

Two individuals, one in their twenties and another in their thirties, were arrested in March on suspicion of offences under the Official Secrets Act. The suspect in his twenties had contacts with MPs from the ruling Conservative Party, including Security Minister Tom Tugendhat and Alicia Kearns, the chairman of the Commons foreign affairs committee.

During a meeting on the margins of the G20 summit in India, Sunak specifically raised concerns about interference in the UK's parliamentary democracy with Li. He emphasized the importance of engaging to address these concerns rather than simply shouting from the sidelines.

Li responded by stating that trade and economic cooperation should be separated from politics and security. This incident is considered to be an epoch-defining breach of security involving a hostile state in the UK's parliament. It follows previous warnings from domestic intelligence service MI5 about Chinese government agents engaging in political interference activities.

In July, the Commons intelligence and security committee reported that China was aggressively targeting the UK and that the government lacked the necessary resources, expertise, and knowledge to effectively respond. Despite these concerns, Sunak defended the recent visit to Beijing by his foreign minister, James Cleverly.

He argued that engagement allows for direct expression of concerns, which he believes to be a more powerful approach. However, the government has acknowledged the seriousness of the situation and the need to learn from it. The police and other agencies are expected to take appropriate actions, possibly leading to a reassessment of the system for handing out parliamentary passes.