LONDON – In a significant display of opposition, the leader of Britain’s main opposition party joined a protest on Saturday against the proposed establishment of a new Chinese embassy in London. This demonstration comes just days ahead of the government’s decision on whether to authorize or reject the project.

Kemi Badenoch, head of the Conservative Party, called on the Labour government to deny the proposal. She cited actions by the Chinese government that included “harassing and sanctioning” members of the UK Parliament and “mistreating British citizens with ties to China.”

“We must confront China’s misconduct,” Badenoch declared to the crowd of protesters gathered at the proposed embassy location. She expressed concern that the current government appears hesitant in its stance against China, as the demonstrators chanted, “no China mega embassy.”

The rally also featured speeches from politicians representing various opposition parties, reflecting a broad spectrum of political resistance to the embassy plans.

Following years of delays and legal hurdles, the UK government faces a Tuesday deadline to decide on the fate of what could become the largest Chinese Embassy in Europe. The proposed site, located at the former Royal Mint near Tower Bridge, is anticipated to receive approval for development.

China has complained about the seven-year delay in approving the project, saying the U.K. was “constantly complicating and politicizing the matter.”

Prime Minister Keir Starmer has stressed that while protecting national security is nonnegotiable, Britain needs to keep up diplomatic dialogue and cooperation with the Asian superpower.

Approving the embassy would pave the way for a long-anticipated trip by Starmer to China, and an expansion of the U.K. Embassy in Beijing.

Opponents say the 20,000 square-meter (215,000 square-foot) Chinese Embassy complex, near London’s financial district and close to crucial data cables, will be used as a base for espionage and for the surveillance and intimidation of Chinese dissidents in exile.

Britain’s intelligence and security services have issued a series of warnings about Chinese espionage activity. In November, the MI5 domestic intelligence agency issued an alert to lawmakers warning that Chinese agents were making “targeted and widespread” efforts to recruit and cultivate them using LinkedIn or cover companies.

However, U.K. security services are thought to have OK’d the embassy development.

Some security experts say the risks are manageable and that the embassy has the advantage of consolidating China’s current seven diplomatic premises in London onto one site.

Ciaran Martin, the former head of Britain’s National Cyber Security Centre – part of the GCHQ intelligence agency – said that no British government would override the security services if they said that the project was too risky.

“Unless we want to sever diplomatic relations with China, the location of their embassy becomes an issue of practicalities, security assessments and counterintelligence operations,” he wrote in The Times of London.