The UK government’s decision to approve plans for a new Chinese mega-embassy in central London has raised concerns around the security of an extensive fiber optic cable network located nearby.

Prime Minister Kier Starmer approved the plans for the embassy, based at a site at Royal Mint Court near the Tower of London, which Beijing bought back in 2018 for £225m. At 20,000 square meters, it would be the biggest embassy of its kind in Europe.

However, an extensive fiber optic network of cables are located nearby, which has prompted concerns around national security.

Cables located near the embassy carry sensitive information, and connect to key financial hubs in the City and Canary Wharf.

BBC reports that planning application shows all of the cables nearby that are owned by UK telco giant BT, with a significant number of connections going into Royal Mint Court, and the Wapping Telephone Exchange to the north of the site. Other operators also have cables there.

Despite this, the Home Secretary, Shabana Mahmood, has approved the plans, noting that concerns around the cables have been considered.

“The Secretary of State does not consider that general national security concerns arising from the identity of the applicant alone are a material planning consideration,” notes the government in documents related to the planned build. “However, in so far as the national security concerns arise out of, or relate to, the development proposed, he [Secretary of State] considers that such matters are capable of being material planning considerations.

“There is no suggestion that the operational development permitted by any grant of planning permission would interfere with the cables, nor that a lawful embassy use of the site would give rise to any such interference.”

Rival political parties have slammed the decision, with the Conservatives calling the decision to approve the build an “act of cowardice,” and a “shameful super embassy surrender.” The Liberal Democrats called it Starmer’s “biggest mistake yet.”

The approval was put on hold for a number of years and comes ahead of Starmer’s planned visit to China later this year, when he will become the first Prime Minister to visit the country since Theresa May in 2018.

In a separate report this week, The Times reported that government security agency MI5 plans to relocate critical Internet cables away from the embassy in an effort to reduce the risk of espionage.

As reported by The Times, MI5 wrote to the home and foreign secretaries to warn that it was unrealistic to “eliminate every potential risk” posed by the new site.

“MI5 has over 100 years of experience managing national security risks associated with foreign diplomatic premises in London,” wrote Sir Ken McCallum, the MI5 director-general, and Anne Keast-Butler, the GCHQ director.

“It is not realistic to expect to be able wholly to eliminate each and every potential risk. [However] it would be irrational to drive ‘embassy-generated risk’ down to zero when numerous other threat vectors are so central to the national security risks we face in the present era.”

The timing of the announcement comes in the same week that the European Commission (EC) outlined proposals to phase out so-called high-risk suppliers, set to include Chinese companies, after revealing its revised Cybersecurity Act.