London’s former spy hubs reopen as ultra-luxury heritage hotels

Raffles London at The OWO makes the stronger case for itself because the building remains the story. The hotel opened on 29 September 2023 after a six-year restoration of the former Old War Office on Whitehall, a 1906 building designed by William Young that once housed Winston Churchill and Lord Haldane. With 120 rooms and suites, 85 private residences, a Guerlain Spa and restaurants and bars including dining by Mauro Colagreco, the property is expensive, but its sense of place is unusually hard to fake.

That is what separates The OWO from many high-end conversions. The Whitehall address is not decorative; it is central to the experience. Churchill worked there between 1919 and 1921, and the building’s military pedigree is still visible in the way the hotel presents itself as a restoration of power, not just a redevelopment. Even with the layers of hospitality added by Raffles Hotels & Resorts and Accor, the old War Office still reads as the main attraction.

The Chancery Rosewood, which opened on 1 September 2025, is more polished and more overtly glamorous, but it leans harder on spectacle. Set in the former U.S. Embassy at 30 Grosvenor Square in Mayfair, the Grade II listed building was originally designed by Eero Saarinen in 1960 and restored by Sir David Chipperfield. The hotel has 144 suites, eight restaurants and bars, an Asaya Spa and the European premiere of Carbone. Its history is real, and the American diplomatic connection to Grosvenor Square runs back to the late 18th century, when John Adams lived there from 1785 to 1788.

Still, the Chancery Rosewood feels more curated than inhabited. Its scale, dining lineup and spa offer a broad luxury package, but the experience is more about orchestration than revelation. Rosewood Hotels & Resorts has built a destination with serious pedigree, yet much of its appeal comes from the performance of exclusivity in Mayfair rather than from the building’s own voice.

For travelers deciding where the money goes furthest, the answer depends on what is being purchased. The OWO earns its price through restoration, continuity and the rare feeling that Whitehall’s history was never stripped away. The Chancery Rosewood earns its price through breadth, polish and a concentrated dose of Mayfair theatre. One is a hotel that grew out of its building. The other is a luxury production staged inside one.