Across the road from the historic Tower of London, and beside the city's bustling financial district, sit perhaps the most controversial buildings in Britain right now — the old Royal Mint Court.
The centuries old, Grade II listed Georgian buildings, and their modern additions, have remained largely empty since the last gold sovereign was minted there in 1975 and operations moved to Wales.
But now, China wants to turn the two-hectare site into what many in the United Kingdom are calling a "mega embassy".
After a series of delays, the UK government must decide this month whether to approve the plans or not.
If it says yes, the Royal Mint Court site won't just become the biggest embassy in London, it will become the biggest in Europe.
Beijing bought the mint in 2018 for £255 million.
Since then, there have been protests outside it about China's human rights record, objections in parliament, and warnings from the British intelligence community that it could become a "nest of spies".
But there could also be diplomatic and economic gains for the UK if it gives Beijing's grand plans the go-ahead.
Redacted floor plans
The UK's community of Tibetans, Uyghurs, Hong Kong exiles, Taiwanese, and Chinese dissidents are strongly opposed to a new Chinese embassy on the site.
"For us, we see this as the UK giving the Chinese government a gift," Tenzin Rabga Tashi from the Free Tibet group told 7.30.
"You can't give that regime a gift such as this, a massive embassy.
"It doesn't sit right with any of us."
That's largely because of an incident in 2022, when a Hong Kong pro-democracy protester was dragged inside the Chinese consulate compound in Manchester and beaten.
Bob Chan was injured but managed to escape with the help of police and other demonstrators — the whole incident caught on camera.
Two months later, China sent six of its officials home, including one of its most senior diplomats.
Opponents of the so-called mega embassy in London are also uneasy about the proposed floor plans, which have some areas redacted.
In August, the government demanded to know what was "greyed out" before it would make a decision.
China explained some rooms but not others, claiming the United States did not submit floor plans for its new London embassy.
"Inside, that's the main issue for us," Mr Tashi said.
"There are a number of horrors that we can only imagine would take place inside, especially with the redacted floor plans.
"We have no idea, the government has no idea what these areas, what these rooms and floors would be used for."
Cables, economics and an internal threat
It's what lies beneath the ground that has others concerned.
Former British Army intelligence officer Philip Ingram said he believed approving the embassy would be "a mistake", because it sits on top of cables carrying sensitive data for London's two financial centres, the City of London and Canary Wharf.
"I think it accelerates [the Chinese] ability to influence what's going on in the City of London and take that data and use it to China's advantage for decades and decades ahead," Mr Ingram said.
"China's intelligence services have three priorities for collection: economics, economics, economics. Anything that gives them economic advantage.
"So, you've got a massive insider threat sitting in the City London when their number one intelligence collection priority is anything that gives them economic advantage — that's the problem."
Conservative MP Tom Tugendhat has also been a strong opponent of the embassy.
"I think it's a pretty extraordinary site for a major development for a country that has demonstrated itself to be extremely hostile to UK interests and has already threatened UK national security in many different ways," Mr Tugendhat told 7.30.
"It's not so much that it's in the centre of London … we have embassies from [other] countries with whom we don't have great relations in the centre of London.
"The difference is this site [because] there's cables that connect our financial infrastructure, and of course it sits opposite the Tower of London so it makes a hell of a statement about UK investment and the security of the City of London and the financial heart of the country."
Britain's security services have been investigating whether it would be a super surveillance hub, and if so, if they could mitigate the risks.
"On the entire electronic warfare front, the UK has to step up for lots of reasons, and if those cables are vulnerable, we should either move them or work out a way to protect them," Isabel Hilton, a British journalist who has covered China for decades, said.
"We have a serious problem of electronic surveillance by the Chinese, of penetration of systems and we have to step up. I think that ought to be a problem that's fixable."
Professor Steve Tsang, the director of London's SOAS China Institute, said he would be surprised if the UK government's cyber security experts had not already studied the Royal Mint Court site thoroughly.
"If they feel that it poses a national security threat that cannot be overcome, then the site would be the wrong site and it should be rejected quite clearly and openly, but if it's a problem, relocating the substation should resolve the problem," Professor Tsang told 7.30.
"That should be the condition of the approval ... with the Chinese government being asked to pay for the cost for the relocation of the telecom substation.
"I think the Chinese government will understand that, and if they really want that site, I don't think paying a few million pounds to relocate the substation is going to be a deal breaker."
Spying allegations
Alongside the embassy controversy, there has been a wider breakdown in trust between the UK and China.
In 2023 two British men, Christopher Cash and Christopher Berry, were accused of spying for Beijing.
Prosecutors dropped the charges in September 2025, saying they did not have enough evidence.
A month after the trial collapsed, MI5 issued a rare 'espionage alert' to all Members of Parliament, Members of the House of Lords and parliamentary staff, about two Chinese agents posing as online recruiters trying to infiltrate parliament.
At the time, Security Minster Dan Jarvis said this was "a covert and calculated attempt by a foreign power to interfere with [Britain's] sovereign affairs in favour of its own interests".
"This government will not tolerate it," he told the House of Commons.
Officials from the Chinese Embassy in London, which has had a presence in the city for more than a century, said the alert was "pure fabrication" and "malicious slander".
Beijing responded too, with foreign ministry spokesperson Mao Ning describing the espionage alert as "baseless and self-serving sensationalism".
"China never interferes in the internal affairs of other countries, nor does it have any interest in collecting so-called intelligence from the UK Parliament," she said.
'Needless provocation'
It is against this backdrop that British Prime Minister Sir Keir Starmer is expected to announce his government's decision about the Chinese embassy by December 10.
Also at stake is an upgrade to the UK's embassy in Beijing, which China is yet to approve.
"If the UK says no at this point after endless delays, then it's a kind of needless row, we don't gain anything," Hilton told 7.30.
"The UK loses the chance to upgrade its embassy in Beijing, which it needs to do, and nobody wins. This is just, I think, needless provocation.
"We've had a long time to think about it, and we should have put in place any security provisions that we need."
Hilton said she thought a 'no' would hurt diplomatic relations, but that trade would continue, largely because the UK depends on China for critical minerals.
"We need them, everybody needs them … it's very easy now for China to apply pressure because we have created these dependencies," Hilton said.
China is the UK's third largest trading partner.
Sir Keir is reportedly planning a trip to China in January, which would make him the first British leader in seven years to go there.
Critics fear the China visit is a sign the government's approval of the London embassy is all but assured.
"We're seeing a government in the United Kingdom that simply is unwilling to recognise that we are in a genuine struggle with the Chinese Communist Party and its way of shaping the world," Mr Tugendhat said.
Professor Tsang said China was a "very big reality for the UK" and engaging strategically with Beijing was essential.
"The idea that the UK can simply ignore China and not engage with China is unrealistic and ridiculous," he said.
"Let's not forget that diplomacy is a luxury among friends, but diplomacy is absolutely essential between non-friends.
"So the more that we actually realise or see China as posing some elements of security threat to us, the more important it is that we engage effectively with China, but doing so with our eyes wide opened."
The ABC requested an interview with the Chinese Ambassador to the United Kingdom, Zheng Zeguang, but the embassy's press team did not respond.
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