LONDON — One of the UK's top planning lawyers has said it would be "unlawful" for the government to grant planning permission for a Chinese "mega embassy" near the Tower of London.

The opinion, from Lord Banner KC, was submitted to the government on Monday, just ahead of the final deadline for those opposed to the scheme to have their say.

Opponents are stepping up their fight against China's plan to turn the historic former home of the Royal Mint into the largest embassy of any country in Europe.

Residents of flats forming part of the Royal Mint estate commissioned the legal document in a bid to derail the scheme, as they fear China, which is now their landlord, will ultimately force them to leave their homes.

China is looking to develop Royal Mint Court into a replacement for the far smaller premises it has occupied a few miles away in the West End of London since 1877.

Former housing secretary Angela Rayner called the scheme in last year, ensuring the final decision on the planning application would be taken by her and not Tower Hamlets Council.

One of the most contentious aspects of the planning application has been that sections have been "greyed out" by China, with the intended use of the rooms in question obscured.

In August, Rayner had written to the Chinese side demanding they "explain the rationale and justification for each of the redactions".

Hong Kong dissidents, and other Chinese pro-democracy activists living in the UK, have expressed fears that these rooms could be used to hold and interrogate opponents of China's Communist regime.

China's response, given by planning consultants working on its behalf, was to clarify the use of some rooms, but to decline to do so for others saying, "the internal functional layout for embassy projects is different from other projects".

They pointed to the fact "the application for the new US embassy in Nine Elms did not disclose details of internal layouts".

In his opinion Lord Banner points to the fact that parts of Royal Mint Court are listed and says "it cannot tenably be said that the detail omitted by the redactions could have no possible planning consequences".

He gave examples of what needs to be assessed, including "the potential uses of the redacted rooms, any structural or safety (including but not limited to fire safety) implications of any physical structures".

Lord Banner also highlights that, no matter what assurances are given, the People's Republic of China (PRC) would "benefit from diplomatic immunity" for any activities occurring on that territory, giving "'carte blanche' in relation to what goes on in the rooms".

He called on Rayner's replacement, the new Housing Secretary Steve Reed, to be provided with unredacted plans, as planning permission "cannot lawfully be granted on the basis of the redacted plans".

A second area where there has been concern about the plans is that China wants to leave one section of the embassy site open to the public so people could view the ruins of a Cistercian abbey and also visit a Chinese heritage centre it hopes to build.

Earlier in the year, the Foreign Office and the Home Office had said this posed "specific public order and national security risks", because they feared that if there was a security or health alert in that paved forecourt, the emergency services would not be able to deal with it.

Any member of the public, including anti-China protestors, could walk into the area — but the police could not enter, as the land would be Chinese territory with "diplomatic inviolability".

They requested China enclose this section inside the embassy's security perimeter. Beijing has declined to do that.

Instead, it said it would agree, as a planning condition, that police or emergency services would be allowed to access the land, if necessary.

In his opinion, Lord Banner says this solution is not adequate, because it would "not be enforceable given the immunity conferred on the Embassy, the Ambassador, and other Embassy employees by virtue of... the Vienna Convention".

"In law the PRC's assurances are meaningless," he says, adding: "The PRC would be free in domestic and international law to U-turn on them at any time and there is nothing that planning conditions could do to stop this."

Despite Rayner's sudden departure, the Ministry of Housing, Communities and Local Government (MHCLG) has indicated her replacement Reed is still expected to make a decision on or before 21 October.

A MHCLG spokesperson said it would not be appropriate to provide ongoing commentary which could prejudice any final decision.

The Royal Mint Court Residents' Association said that with Lord Banner's opinion it had "shown why the Chinese Embassy at the Royal Mint cannot be approved".

They said: "The UK government should now put an end to the planning application once and for all, or face a humiliating judicial review."

Reed will have to weigh other issues alongside the planning questions, including serious security concerns.

Conservative politicians have said that if China is allowed to turn Royal Mint Court into its new embassy it could seek to tap into fibre optic cables running near the building that carry sensitive data for financial institutions in the City of London.

The Chinese Embassy in London has previously told the BBC that it "is committed to promoting understanding and the friendship between the Chinese and British peoples and the development of mutually beneficial cooperation between the two countries.

"Building the new embassy would help us better perform such responsibilities". — BBC