Downing Street hopes the embassy will pave the way for new trade deals with Beijing.

British security services have said that the risks posed by the new embassy, close to the data cables linking the City of London to Canary Wharf, was manageable. It is understood they prefer to have the Chinese embassy at one location, rather than the current situation of several sites across London.

At 20,000 square metres, the complex is set to be the biggest embassy in Europe. Picture: David Chipperfield Architects

Last week, An intelligence expert told LBC that the plans were ‘completely mad’.

Anthony Glees, a professor of intelligence and security at the University of Buckingham said that the proposed site at Royal Mint Court sits alarmingly close to fibre-optic cables carrying vast amounts of financial and communications data from the City of London and Canary Wharf.

Local Government Secretary Steve Reed approved the plans for the building at Royal Mint Court.

The decision removes a diplomatic hurdle in the relationship with Xi Jinping’s government, clearing the way for Sir Keir Starmer to make a widely-expected visit to China – possibly within weeks.

But critics of the scheme plan to challenge the decision in the courts, with local residents raising money to launch a judicial review against the project.

Professor Glees told LBC: “What people call the cloud isn’t in the sky, it’s in the ground,” he said, pointing to the underground cables.

“You can see from the plans how close rooms run to those cables. They can be tapped very easily.

“There are also heating systems suitable for large servers. In my view, this would not just spy on the UK, it would become the Chinese intelligence hub for the whole of Europe.”

He also raised concerns about the size and design of the embassy complex, suggesting it could facilitate intimidation or detention of critics, referencing the 2022 incident in which a Hong Kong democracy protester was dragged into the Chinese consulate in Manchester and assaulted.

The application was first submitted by China in 2018 and was subjected to repeated delays.

After planning permission was initially rejected by Tower Hamlets Council, Sir Keir Starmer “called in” the decision to be assessed by ministers at the request of Xi Jinping, the Chinese president, in 2024.

Beijing sought to keep the details secret by redacting all publicly available versions of the plans.

They show a concealed chamber that will sit about a metre from fibre-optic cables that transmit financial data to the City of London, as well as email and messaging traffic for millions of internet users.

Luke de Pulford, head of the Inter-Parliamentary Alliance on China, said: “Years of campaigning about the obvious and manifold risks posed by this embassy development have not been enough to outweigh the UK Government’s desire for Beijing’s money.”

The decision comes despite a call from MPs and peers on the Labour-led Joint Committee on the National Security Strategy to reject the plans, warning the embassy – the biggest in Europe – would “create a hub for expanded intelligence-gathering and intimidation operations”.

A Government spokesperson said: “This planning decision has been taken independently by the Secretary of State for Housing. This follows a process that began in 2018 when the then Foreign Secretary provided formal diplomatic consent for the site.

“More broadly, countries establishing embassies in other countries’ capitals is a normal part of international relations.

“National security is our first duty. Intelligence agencies have been involved throughout the process and an extensive range of measures have been developed to manage any risks.

“Following extensive negotiations in recent months, the Chinese Government has agreed to consolidate its seven current sites in London into one site, bringing clear security advantages.”