A controversial plan to build China’s largest embassy in Europe came under renewed criticism this week after a British paper obtained access to unredacted blueprints that showed a secret, underground room lying only meters from sensitive fiber-optic cables. The revelation came as British Prime Minister Keir Starmer is expected to approve the project before a planned visit to China later this month.

According to The Telegraph, the drawings they reviewed “show that a single concealed chamber will sit directly alongside fibre-optic cables transmitting financial data to the City of London, as well as email and messaging traffic for millions of internet users.” That long, narrow chamber is redacted in publicly available documents.

“China won’t say what the basement is for. It could be legitimate classified communications equipment, but that can hide a multitude of sins,” warned British security expert Professor Alan Woodward. “There’s a long history of cable-tapping by East and West alike. Anyone who can do it has done it. Espionage isn’t just about state secrets. Economic intelligence is central to the mission of foreign intelligence services.”

Drawings reviewed by The Telegraph also show the room will be “fitted with hot-air extraction systems, possibly suggesting the installation of heat-generating equipment such as advanced computers.” As part of the construction project, the outer wall separating the basement room from the communications cables would be demolished and rebuilt.

Woodward called the demolition of the basement wall a “red flag.” He explained that, “If they wanted to tap the cables, they wouldn’t need to go far. You wouldn’t know what was happening down there.”

The Telegraph also uncovered the purpose of other redacted areas in the planned embassy basement, including “emergency back-up generators, a sprinkler plant, new lift shafts and communications cabling. The plans also conceal bathrooms and showers.”

These were just the redacted parts of the basement plan, which included 208 rooms in total. The entire embassy site — formerly home to the Royal Mint — covers 22,000 square meters, or roughly 236,000 square feet. If approved and completed, the so-called super embassy would be China’s largest in Europe.

Unsurprisingly, when China first purchased the property for $300 million in 2018, China-watchers soon sounded the alarm. At first, local officials rejected the proposal based on fears that a Chinese embassy would attract large protests, impacting residents and tourists alike.

However, China resubmitted the embassy plan to the Labour government that assumed power last year, and Prime Minister Keir Starmer is expected to approve it to smooth the way for a trip to China earlier this month.

Starmer explained the reasoning for his China trip in a December Guildhall speech. “President Trump met President Xi in October … and will visit China in April. Since early 2018, President Macron has visited China twice, and he’ll be there again later this week. German leaders have visited four times, and Chancellor Merz will be there in the New Year. Yet, during this same period, no British Prime Minister has visited China. … The absence of engagement is just staggering — a dereliction of duty.”

The purpose of the trip would likely be to foster business deals. The last time a British prime minster visited China (Theresa May in February 2018), the business delegation on the trip signed deals worth £9 billion.

Starmer represents a Western attitude that has played right into China’s hands for far too long. In November, MI5 warned British lawmakers that Chinese agents were aggressively recruiting them with “targeted and widespread” efforts. Instead of confronting China over its aggressive espionage, Starmer has planned a business trip to China instead; there is a lot of money there, after all. And, to make his business trip happen, Starmer is prepared to green-light a massive Chinese building project in the heart of London, which would only further enhance China’s espionage efforts.

If nothing else, Starmer’s actions suggest that he does not view China as a serious threat.

Yet Chinese espionage does pose a serious threat. Even lawmakers in Starmer’s own party oppose the plan over “the recent track record of Chinese espionage cases, interference activities, and issuing of bounties against U.K.-based Hong Kongers.”

“Even forgetting for the moment that there is a secret basement one meter away from sensitive cables, Britain should not be giving approval for any expansion of China’s embassy,” Asia expert Gordon Chang told The Washington Stand. “These embassies are outposts for subversion. Why would we want to expand them? And just because Washington made a critical mistake to have that embassy site overlooking the capitol of the United States doesn’t mean the British need to make a similar mistake.”

If the British will not learn from America’s mistakes, perhaps American leaders can learn from theirs. Simply put, China wants to advance their own interests at the expense of their geopolitical rivals, like the U.S. They will do this through espionage, cyberattacks, intellectual property theft, unfair trade practices, and even secret police actions against dissidents on American soil. When American leaders are lured by the prospect of lucrative business deals with China, they should remember the long game China is playing and conclude that the security cost is far greater than any economic gain.