LONDON — China’s plans for a giant new embassy opposite the Tower of London have been unanimously rejected by local councilors on the grounds they pose a security risk to local residents, in a surprise decision that comes amid growing concerns over Beijing’s diplomatic activity in the United Kingdom.

The London Borough of Tower Hamlets had indicated it was preparing to wave through the proposals drafted by the embassy’s architect, David Chipperfield, as recently as Wednesday, telling CNN then that the proposed initiative was “generally in accordance” with the area’s development plan and that “on this basis officers have recommended that planning permission and listed building consent are granted.”

Yet at a marathon meeting that continued late into the night on Thursday, the council was persuaded to block the proposals on the basis that they presented a risk to locals’ safety and would impede traffic in this densely populated part of east London, close to the capital’s financial district and a block from Tower Bridge.

A Tower Hamlets Council spokesperson told CNN: “The committee resolved to reject the application due to concerns over the impact on resident and tourist safety, heritage, police resources and the congested nature of the area. The application will now be referred to the Mayor of London before the final decision is issued.”

The council’s decision puts the British government in a difficult position. It could use its powers to “call in” the plans and overrule the local council’s decision, which could be politically controversial; or refrain from intervening and risk antagonizing Beijing.

China purchased the historic parcel of land, called Royal Mint Court, in 2018 for around $312 million from a property company, and had intended to transform most of the 5.4 acre plot into a super-sized diplomatic mission, with room for hundreds of staff and a cultural exchange. Royal Mint Court had previously been owned by the British monarchy and was once the home to the facility that manufactured Britain’s coinage.

Among those who spoke at the council meeting was David Lake, chairman of the Royal Mint Court Residents’ Association, representing 100 families whose apartments now find themselves on Chinese-owned land next door to what would have been the embassy’s rear perimeter wall.

Thursday’s decision came the day after CNN revealed that Lake had written to King Charles to highlight the residents’ concerns and request that the Crown buy back the rights to their properties’ land after multiple, fruitless appeals to local and national lawmakers.

When it still owned the land about 30 years ago, the Crown Estate, which manages the British monarchy’s non-private property interests, built a set of low-rise apartments on part of the site as part of a government scheme to provide homes for “key workers” such as police officers and nurses. Queen Elizabeth II was pictured opening the estate in 1989.

Owners of the new apartments were granted a 126-year lease over the land, a common practice in British property law where residents own the bricks and mortar of their property but another entity, a freeholder – now China – owns the ground on which it is built.

The rejection of the plans at a local level – while the national government appeared loath to get involved – will likely prove embarrassing for Beijing at a time when the behavior of China’s diplomats is under scrutiny after a protester was dragged into the country’s consulate in Manchester and beaten.

Police in Manchester are currently investigating the episode. Consul General Zheng Xiyuan said he acted because he found the protester’s posters offensive to his homeland.

China has also been accused recently of using its diplomatic outposts and loosely affiliated community associations, in effect, as overseas police stations to monitor Chinese citizens abroad and coerce them to return home. British lawmakers have expressed concerns over reports of three such premises in the UK.

China’s embassy proposals had run into stiff opposition from locals in this part of London, concerned about the impact of possible protests outside the complex and inadequate protection from a possible terrorist attack. Many complained repeatedly that they had not been adequately informed by China’s advisers as they were drawing up the blueprints for the site.

China’s planning representatives can appeal the decision or submit alternatives plans for review.

Beijing may also seek support in a more discreet fashion from Britain’s central government in Westminster, where China has often reminded decision-makers of the economic ties that underpin UK-China relations.