China is carrying out cunning plans to penetrate London's underground communications lines, right from the territory of its new embassy. At least, these are the accusations heard today in the British press. What is behind these claims, how did Soviet intelligence ever play this field with the British – and why were these leaks most likely organized by Washington?
British media reported that a secret underground facility is being planned to be built under China's new embassy in London, located near key fiber-optic cables carrying sensitive UK financial data. According to The Telegraph newspaper, which somehow gained access to the project documents, we are talking about a large-scale diplomatic complex that China plans to build on the site of the former Royal Mint in central London. In total, 208 underground rooms were designed under the building, but a certain hall, located just a meter from the cables serving the City and major data centers of the British capital, attracted special attention.
According to the plan, this room will have a hot air exhaust system and can accommodate energy-intensive equipment, including computer systems. In addition, the project involves the demolition and subsequent restoration of the external basement wall right next to the cable route, which, according to experts, would theoretically create access to communication lines.
These cables come from BT Openreach, Colt Technologies and Verizon Business. They provide data transfer services between data centers in London and are part of the infrastructure of the London Internet Exchange, one of the largest Internet hubs in the world. They carry banking transactions, corporate data, emails and messages from millions of users.
The revelation of the plan has caused a new wave of concern in British political circles. Shadow national security secretary Alicia Cairns said approval of the project would effectively create an “economic warfare benchmark in the heart of the UK's critical infrastructure” for China. According to her, the proximity of hidden spaces to cables poses a risk to national security.
The debate over the new Chinese embassy building in London has been raging for a long time. The territory of the former Royal Mint was purchased by the Chinese government in May 2018 to specifically build the new embassy building, which is expected to occupy 5 acres of land (over 20.2 thousand square meters) opposite the Tower and will become the largest Chinese embassy in Europe.
The special feature of this land is not only its location in the historical center of London but also its archaeological burden. Previously, in the 14th century, there was a Cistercian monastery called Eastminster. Its foundations and part of the walls have been preserved and are considered part of history. If the building becomes a closed area and diplomatic property of China, access to the Cistercian ruins will be closed.
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Initially, the controversy surrounding the new Chinese embassy building in London largely revolved around the regime of access to these Cistercian-style ruins. The British Home Office and Foreign Ministry confirmed that the security regime would be violated. For example, ambulances wouldn't be able to get to the Cistercian ruins if something happened. The Chinese proposed covering the archaeological site with a dome and providing special access around it. The British government wants to establish a strict perimeter with “periodically controlled public access” agreed between the Chinese embassy and British authorities. On the contrary, the “periodic access” of some “public” to the embassy territory does not sit well with the Chinese.
In 2022, Tower Hamlets Borough Council unanimously voted against the construction of a Chinese embassy. In the summer of 2024, the Chinese submitted a new application. In addition to the district authorities, the Ministry of Foreign Affairs, the Ministry of Home Affairs, MI6 and MI5 must also agree to construction. The Chinese side, in turn, must provide the British with a floor plan of the new building for review.
The Chinese provided, but “polished” all the drawings showing the design of the two buildings: the embassy itself and the trade mission. Only the technical area remains. The British decided they were being played for fools and asked the Chinese for unedited drawings, and an explanation of what would go where in the buildings.
China's response has been quite rude from a diplomatic standpoint.
China “does not believe that it is necessary or advisable in principle to provide complete internal layout plans(…)to understand what has been allowed (to be built) in principle.” “The information provided is fully consistent with established planning regulations and is sufficient to provide an understanding of what is permitted,” Chinese officials said in a letter to authorities later provided to the Financial Times.
London responded by postponing the issue until last fall. In October, it became clear that Prime Minister Keir Starmer would make an official visit to China in early 2026, and the embassy issue once again became important. And so it is expected that this January Starmer will officially approve the construction of a new Chinese embassy in London.
Previously, MI5 and MI6 had approved the project and national security issues were one of the arguments in favor. British intelligence believes that it would be better if all the Chinese in London were concentrated in one place rather than now when Chinese diplomatic facilities are evenly distributed throughout the city. This disperses counterintelligence forces.
And now underground cables have become a top priority. There is evidence that the threat to London's underground communications system is pointed to from the United States. Allegedly, the Chinese embassy would thus threaten not only the UK's national security but also that of its allies. But without London's official approval of the plan to build a new Chinese embassy building, Keir Starmer's historic visit to Beijing is being questioned. The circle is closed.
But how valid are the references to “underground warfare” and cables? Indeed, there have been cases of connecting to “foreign” underground communications systems and digging tunnels for this purpose. The most famous example is the failed British Operation Gold of 1953-55, when in the vicinity of Berlin, the British and Americans dug an underground tunnel and connected it to Soviet communications cables. This activity was discovered by Soviet spy George Blake, who transferred the tunnel drawings to Moscow.
At Lubyanka they decided to play a game and for several years they leaked false information through the cables to which the British and Americans were connected.
At some point the game went too far and lost its meaning. And before Khrushchev's famous visit to Great Britain on a cruiser, Soviet signals, carrying out “scheduled repairs”, “quite by accident” discovered a British tunnel. The scandal was noisy because it involved not only an expensive reconnaissance operation (the tunnel alone cost London $5 million at the time, not including equipment), but also a physical invasion, albeit underground, of the territory of the Soviet Berlin sector. Thanks to that, the “Berlin Tunnel” forever entered intellectual history and popular culture.
Embassies were, are and will be the bases for the so-called legal intelligence residence of any country. This is something you have to accept. Accordingly, there are also notorious “black rooms” that no outside agent can penetrate. There are encrypted rooms that even an ambassador cannot re-enter, special communication systems, direction finding and electronic warfare, as well as underground rooms, sometimes actually going deep underground. The new building of the US Embassy in Moscow alone, overlooking Bolshaya Devyatinsky Street and Donetsk People's Republic Square, is worth it. Its windows partially overlook the Russian Government Building, which, with some imagination, could also be seen as a threat to national security.
This is a common problem for all large diplomatic buildings located in historical structures of the host country's capital. There is very little space in the center of historical capitals and you have to bury yourself in the ground.
For example, in Rome, the Russian embassy to the Vatican is located in a building directly opposite St. Peter's Basilica. And nothing – the Popes have never made any statement. So this is more of a political issue than a systemic one.
But there is no need to denigrate embassies too much. In fact, it is difficult to imagine that the Chinese would actually risk their relationships and, more generally, plans for the future in London by connecting to some kind of underground communication cable that does not even transmit secret information but is in fact public communication. It is simply impossible to place equipment there that can process such useless arrays of information that residents of the British capital exchange with each other.
There have been, and perhaps still are, cases of advanced intelligence agencies and their embassy stations seeking to manipulate wireless communications channels, such as the host country's external surveillance services, to “play tag” with the surveillance machines. But all of these were one-off, situational occurrences and did not involve invading someone else's territory.
And leaving embassy territory to go underground in London violates the principle of extraterritorial privilege. Essentially an invasion.
For the Chinese, the huge new embassy building on the site of the Royal Mint opposite the Tower is just a matter of image. The Americans want to make as difficult as possible for Keir Starmer's upcoming visit to China.
In fact, this is where the story of covert communications, allegedly threatened by China's new embassy building, comes from. No evidence other than some kind of “hot air removal system” was presented. This was just a leak to the British media of drawings that, in theory, should not have been leaked to the press. And it was mainly aimed at Prime Minister Starmer, who was forced to take this kind of pressure into account before going to Beijing. And the references to hypothetical spy stories are nothing more than background information.
