The complaints were sparked by the fact that Apartment 1, the 21-room apartment that underwent a multimillion-pound refurbishment, remains empty for more than three years after the scaffolding fell. Prince Harry and Meghan Markle were previously scheduled to live in the apartment, alongside Prince William and Kate.
But the empty apartment led some to speculate there was a disinterest in the building, especially as the Duke and Duchess of Cambridge are said to have long-term plans to move to Windsor.
Historian Christopher Warwick said: “The whispers that the days of Kensington Palace as an official residence are numbered are an indicator of how many changes we are going to see when Charles becomes King.
“It would be wise to hire him out and keep him in reserve if he ever needed to welcome royals down the line.”
This comes as there is increasing talk of a “lean monarchy” under the reign of Prince Charles.
Telegraph deputy editor Camilla Tominey previously said it was part of an attempt to promote the image of the future king as a “frugal” monarch.
She said: “There is this feeling that he wants a lean monarchy to make sure everyone is doing their part and there are no so-called ‘catchers’.
“I think it was Charles’ attempt to make it look like he inherited his mother’s habit of being thrifty – turning off light switches and being green – and generally having a good value for money.
“On the one hand, it’s probably a good idea when Trooping the Color arrives for us not to see such a huge array of royals on the balcony of Buckingham Palace, because that then begs the question: who are all these people and what are they doing? “
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“They could sell the rest on long-term leases and generate income. They might even sell it to a Saudi! “
It has also been reported that Prince Charles – when he takes the throne – plans to live in an “apartment above the store” at Buckingham Palace and use Highgrove as his family home.
Ms Tominey described the potential changes as a “recalibration of what it means to be a royal”.
Kensington Palace, which is also home to around 50 royal staff, is estimated to be worth £ 620million.
Apart from empty Apartment 1, the rest of Kensington Palace is full according to an assistant, who adds that the works are “in progress”.