China is waiting for UK Prime Minister Kier Starmer’s approval for its massive new embassy in London. But hidden plans reveal something more worrying. The Telegraph uncovered secret drawings showing a hidden underground chamber right next to Britain’s most sensitive fibre-optic cables. These cables carry financial data and internet communications for millions. The secret room has hot-air extraction systems, hinting at heat-making spy equipment like advanced computers. China plans to demolish and rebuild the basement wall beside the cables, raising alarms about possible spying or sabotage. Shadow national security minister Alicia Kearns said, "The unredacted plans reveal a concealed room running immediately alongside the fibre-optic cables critical to the City and Canary Wharf." She warned approving the embassy would give China "a launchpad for economic warfare at the heart of the central nervous system of our critical national infrastructure." The embassy will span 22,000 sq m on the former Royal Mint site and be the largest Chinese diplomatic mission in Europe. The project has been controversial since China first applied for permission under the last Conservative government. Many planning documents were heavily redacted for "security reasons." The leaked unredacted plans expose 208 rooms, including the secret chamber beneath the Seamen’s Registry building, located just over one metre from cables owned by telecom giants like BT Openreach and Verizon Business. Possible spying methods include wire taps or bending fibres to leak data. Other embassy sections include luxury flats for diplomats, gyms, toilets, and emergency generator rooms. It remains unclear who will build the embassy or the new basement wall. Reports suggest PM Starmer could approve the embassy ahead of his visit to China to meet President Xi Jinping later this month.