The 5,700-square-metre mansion at 2-8A Rutland Gate overlooks London's Hyde Park.

Last year, Hong Kong billionaire Cheung Chung Kiu obliterated London's real-estate record by paying roughly $276 million (R4 billion for a 45-room mansion overlooking Hyde Park.

Now, he reportedly plans to spend roughly that same amount to renovate it.

Cheung has submitted plans to the Westminster City Council for an extensive renovation of the 5,700-square-metre mansion at 2-8A Rutland Gate in Knightsbridge. Per a website that shares information on the renovation, the house is "heavily dilapidated" and requires "extensive refurbishment prior to occupation."

Experts told the Sunday Times that Cheung's proposed renovations could cost as much as $276 million - which is slightly higher than the price he paid for the home last year via his private family office. A spokesperson for the renovation project declined to comment for this story.

Peter Wetherell, chairman of the Wetherell real-estate agency in Mayfair, told Insider that after its renovation, 2-8A Rutland Gate could be worth "anything from £310 million to over £500 million, either way the most valuable private home in London."

A view of 2-8 Rutland Gate in 2015.

Cheung, a Hong Kong real-estate investor whose net worth is estimated at more than $1 billion, bought the home from the estate of Saudi Arabia's late crown prince Nayef bin Abdulaziz. 2-8A Rutland Gate was originally four homes before being combined into one massive building with 45 rooms. The sprawling residence overlooks Hyde Park in Knightsbridge, an upscale neighborhood in central London. It was once listed for £300 million.

When Cheung bought the property in January 2020, he had not yet decided whether he would live in the mansion himself or turn the building into apartments, his spokesperson told The Wall Street Journal at the time. But according to the Rutland Gate renovation website, the property is now intended to be the new owners' family home in London.

A reception room at 2-8 Rutland Gate.

The proposals for the home include altering, repairing, and demolishing parts of the building's façade, according to the website. The owner also wants to change the internal layouts, demolish and remodel the fourth and fifth levels, excavate the basement, and add nearly 11 feet to the building's overall height.

Pending approval from the city council, construction will start in the fourth quarter of 2021 and the family will move in in early 2025. A spokesperson for Cheung's company did not immediately respond to Insider's request for comment for this story.

When it comes to Cheung's personal and family life, he's known for staying under-the-radar, according to Bloomberg. His real-estate purchases, on the other hand, often make headlines.

In 2015, he spent $656 million on a piece of land in Hong Kong's exclusive Peak neighborhood. And in 2017, his company, CC Land Holdings, bought the Leadenhall Building, a 740-foot skyscraper in central London known as "the Cheesegrater."

A bathroom at 2-8 Rutland Gate.

Cheung isn't the only Hong Konger who's been snapping up property in London lately. As Bill Bostock reported for Insider, Hong Kong residents have been rushing to snap up luxury real-estate in the UK capital since China imposed a new national-security law on Hong Kong last summer.

Once a rarity, homes priced at £100 million or higher are becoming more and more common in London, creating a new "giga-prime market for billionaire buyers," according to Wetherell. About 20 homes in central London that are built or in development are currently valued at around £100 million, he said.

"Billionaires like owning trophy homes in London because it is good for their image," Wetherell said in a recent report from his agency. "... And they also like London because each decade property prices go up, so the value of their property assets increase."