LONDON — Rishi Sunak has spent most of his brief premiership treading a delicate balance on relations with China.

So the last thing the British prime minister needed as he enters a careful autumn of diplomacy was a Chinese spy scandal erupting in his midst.

Westminster is this week reeling from the news that a British citizen working as a parliamentary researcher for MPs is under arrest on suspicion of spying for Beijing. Two men, one in his 20s and another in his 30s, were arrested under the Official Secrets Act in March, police confirmed, after the news was reported in the Sunday Times. 

One of the men is a well-known figure at Westminster who was involved in international affairs and had close links to senior Conservatives.

One parliamentary aide who knows the man — granted anonymity to speak freely for this article — said: “Everyone who had come into contact with him is feeling angry and exposed.”

Another person involved in Westminster’s China policy circle added: “It’s hard to trust anyone in the field now. This is a real shock. Everyone wonders what went wrong.”

In a statement released through lawyers, the arrested researcher — who has not been formally named by British police — said he was “completely innocent.” He added: “I have spent my career to date trying to educate others about the challenge and threats presented by the Chinese Communist Party.”

Speaking in the House of Commons Monday, Sunak said he was “appalled” by claims of espionage, but signaled no fundamental change in his approach toward Beijing, which has seen him pave the way for closer engagement with China than his hawkish predecessor Liz Truss.

Sunak said he had been “emphatic” with Chinese Premier Li Qiang during face-to-face talks at the G20 summit in India last weekend that undermining British democracy “will never be tolerated.”

But Sunak was careful not to rule out inviting Chinese officials to the U.K.’s AI safety summit in November, despite pressure from members of his own party to adopt a tougher stance. “AI knows no borders,” a Downing Street spoksperson said.

Tory MP and former Cabinet minister Iain Duncan Smith, one of nine British citizens sanctioned by China in 2021, suggested there is an essential confusion over the U.K.’s treatment of Beijing, given Sunak has resisted calls to formally designate China a threat. “Are they a threat or not?” Duncan Smith asked the Commons.

Tim Loughton, another sanctioned Tory MP, urged ministers to add China to the “enhanced” tier of Britain’s foreign lobbying register, which would give the U.K. home secretary extra powers to monitor agents working on behalf of the Beijing government.

Sunak now faces a split in his Cabinet, with the Times reporting that Home Office ministers Suella Braverman and Tom Tugendhat would support a tougher approach.

In contrast, Business Secretary Kemi Badenoch said Monday that declaring China a threat would “escalate things” further. Officials in both the Treasury and Department for Business and Trade have long balked at the idea, arguing it would cripple the U.K.’s economic ties with Beijing.

Access all areas?

The scandal has also raised questions about the vetting process for people working in the U.K. parliament, given the arrested researcher held a pass giving him access to much of the estate. 

Luke de Pulford, executive director of the Inter-Parliamentary Alliance on China, told POLITICO it was “bizarre” to have the same clearance process for all employees in Westminster, suggesting there should be enhanced vetting for people working chiefly on security matters.

A House of Commons spokesperson responded: “Our vetting is in line with government policy, and follows the national security vetting policy that is set by government. We do not and will not comment on specific cases.”

However, the weekend’s revelations are only the latest in a series of Chinese spy scandals to rock national parliaments around the world, with Canada and Australia among the Western powers to have issued warnings in recent years.

The scandal also follows a series of warnings about Chinese attempts to influence Westminster specifically.

A recent report by the U.K. parliament’s intelligence and security committee said the resources being dedicated to tackling security threats posed by China are “completely inadequate.”

And last year, MI5 issued a rare security alert stating that Christine Lee, a U.K.-based lawyer, had been engaged in “political interference activities” for the Chinese state by cultivating ties with Labour MP Barry Gardiner. She has denied the charges and is suing MI5 for damages.

Beijing has rebutted the latest spy allegations, with a spokesperson for the Chinese embassy to the U.K. stating: “The claim that China is suspected of ‘stealing British intelligence’ is completely fabricated and nothing but malicious slander.”

Eleni Courea and Stefan Boscia contributed reporting.