China’s London super-embassy could hold a secret room next to key data cables

Concerns over Chinese cyber and intelligence activity in the UK have been reignited following a new investigation into plans for China’s proposed ‘super-embassy’ in London which reveals underground rooms near cables carrying sensitive financial data

Covering 22,000 sq m on the site of the former Royal Mint (the official UK maker of British coins) the embassy would be the largest Chinese diplomatic mission in Europe.

The Daily Telegraph reports that unreacted planning documents reveal a concealed underground chamber built directly alongside fibre-optic cables carrying some of Britain's most sensitive financial and internet traffic.

The cables serve the City of London, Canary Wharf, and key data centres linked to the London Internet Exchange (Linx).

Linx infrastructure is critical to banking, communications and national security.

According to the plans — designed by UK architects David Chipperfield — the ‘hidden room’ would sit just over a meter from the cables and include hot-air extraction fans, raising concerns that heat-generating equipment such as high-performance computers could be installed.

The embassy's plans are said to include more than 200 rooms, underground tunnels, background generators and apartments.

Most of the planning documents submitted to Tower Hamlets council were heavily redacted for what China described as “security reasons” a move that led to the then housing secretary Angela Rayner to delay approval in August last year and demand clarification.

What is the Linx cable network and why is the data senstive?

The Telegraph points out that the construction work would place Chinese officials just over one metre from the fibre-optic cables running beneath the pavement – raising the prospect that they could be tapped.

Telecoms cable plans seen by reporters show the fibre-optics running beneath the pavement belong to companies including BT Openreach, Colt Technologies and Verizon Business

The cables are thought to carry signals bearing financially sensitive information related to the British economy, stretching between the Telehouse group of data centres in Docklands and other centres around the capital.

Linked together, these form the core of Linx. Beyond London, they connect to Atlantic cables linking to the US.

The news comes as Prime Minister Keir Starmer is expected to approve the embassy ahead of a planned visit to China later this month, when he is due to meet President Xi Jinping.

It’s notable that much of the coverage about the plans has come from right leaning UK outlets, framing the issue as a failure of The Labour Party's national security credentials and an embarrassment for the new prime minister. However, the combination of a recent China-linked cyber breach and revelations about the embassy's underground design is likely to intensify scrutiny.

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