The Queen's security could be at risk from serial squatters who invaded a building metres away from Buckingham Palace, the property's owners have claimed.
Around a dozen activists moved into the seven-storey property on Buckingham Gate, in the shadow of the monarch's residence, rebranding it the Rogue Embassy.
Court documents cited a Metropolitan Police royal specialist protection officer who flagged a "potential security risk" posed by the group.
Concerns were raised that, if the occupiers accessed the adjoining roof, they could directly peer into the gardens of the royal grounds.
But one of the protesters insisted they were not "going to do anything".
Snipers stationed on the roof of Wellington Barracks were in "regular contact" with a next-door owner to raise concerns about the view into the palace gardens from the roof, the document, seen by the Press Association, said.
The occupiers claim to be part of the Autonomous Nation of Anarchist Libertarians and said they expected eviction efforts to begin on Friday night.
It is the third high-profile building the band of squatters have entered this year.
They were evicted from a multimillion-pound property in Eaton Square, central London last month, before immediately moving into a nearby seven-storey building on Grosvenor Gardens.
The once-lavish property on Buckingham Gate, which neighbours the Swaziland High Commission, has been adorned with flags and banners by its new occupants.
Owned by Bahraini Abdulrahman Aljasmi, it has stood derelict for decades, the group claimed, leading them to repurpose it as an embassy for "indigenous people" and "nations that are not recognised".
A Buckingham Palace spokeswoman said: "We never comment on security, which is a matter for the police."