King George III's royal observatory in Richmond lists for $24 million

The King's Observatory in Richmond, the Grade I listed building George III had built so his family could watch the stars, is for sale for the first time since it went up in 1769. It is listed at 18 million pounds, about $24 million, through Charlie Willis London, and the sale includes planning permission for a substantial expansion.

Architect Sir William Chambers designed the building specifically so the king and his household could observe the Transit of Venus. The original dome is still fixed atop the house, and a visitor can still climb into it, standing where George III once looked to the sky.

The house is now a four-bedroom home of roughly 7,300 square feet, set on nearly seven acres in Old Deer Park, next to Kew Gardens. Property developer Robbie Brothers spent several years converting the former scientific building into a residence, completing the main restoration in 2018.

What the observatory kept from its scientific past

Long before it was a home, the building was a working center for astronomy, timekeeping and weather research, used by the Meteorological Office until 1980. Meteorologist James Stagg worked there and later advised Allied commanders on the weather forecast ahead of the D-Day landings.

A plaque inside the building still records Stagg's name and his role in that forecast, one of the clearest links between the house's scientific working life and the history it now sells alongside. That history survives in the fabric of the house rather than as a museum piece.

The library keeps its original Georgian bookshelves, still holding around 6,000 books, while the dining room is lined with hand-painted wallpaper based on an 18th-century view of Canton.

Outside, the grounds run to almost seven acres and include a long private drive, an ornamental lake and a stone boathouse, alongside several structures left over from the property's scientific era. Parts of the landscape date to work by the 18th-century landscape designer Capability Brown.

The more recent gardens were overseen by landscape designer Kim Wilkie, layered on top of that 18th-century framework. Together they give the property, a few miles from central London, grounds that read closer to a country estate than to a residence inside the M25.

What a buyer could still add

The sale comes with planning permission for a further 10,000 square feet, covering additional living space, staff quarters and underground parking for as many as 17 cars. Built out in full, that would take the residence to nearly 19,000 square feet.

A house tied this directly to a reigning monarch, with permission already granted for that scale of expansion, ranks among the rarer listings to reach the London market in any given year, even among the city's grandest addresses.

We have tracked London's upper end closely this year, including the Park Hyatt Residences now selling on the riverside at Nine Elms, a new-build scheme the observatory's Georgian scale and royal history stand well apart from.

We have also surveyed the city's most exclusive private members' clubs, another strand of high-value London life the observatory is outside of, as a piece of royal scientific history rather than new development or club membership.

Richmond's Old Deer Park, where the observatory is beside Kew Gardens, has long drawn buyers seeking space and quiet within reach of central London, a pull that shows in how our coverage of garage and other high-value categories keeps returning to properties with land attached.

The listing does not name a completion date or confirm a buyer. What it does confirm is scale: a working royal observatory turned into a private house, still carrying the dome, the library and the permission to grow by another 10,000 square feet.