For most of the last century, the building at the corner of Whitehall and Horse Guards Avenue was where Britain ran its army. It held more than a thousand rooms and two and a half miles of corridor, and nobody walked in off the street. Now it is Raffles London at The OWO, and walking in is rather the point.
The argument for The OWO is that it is not only a hotel in a historic building but a public destination in its own right: nine restaurants, three bars, a large spa and a ballroom, set inside Edwardian state rooms that were never designed for guests. That scale is its great strength, and for some travelers, its main drawback.
From the War Office to a front door
William Young designed the building, and it opened in 1906 as the New War Office, a confident piece of Edwardian Baroque built for around 2,500 officials. Winston Churchill worked here as Secretary of State for War from 1919 to 1921. When the Ministry of Defence was unified in 1964, most of the Army Department moved across Horse Guards, and the New War Office quietly became the Old one.
The government sold it in 2014. The new owners, the Hinduja Group and ONEX, took the keys in 2016, and the restoration that followed involved thousands of craftspeople. Raffles opened in 2023. The building is Grade II* listed and now holds the hotel, 85 private residences sold as The OWO Residences by Raffles, and a run of restaurants that draws Londoners who would never book a room. The MICHELIN Guide now rates it a Three-Key hotel, its highest hotel distinction.
The rooms
There are 120 rooms and suites, carved from former state rooms and senior offices, with views over Whitehall and Horse Guards. What these rooms have that new London builds rarely manage is proportion. Edwardian ceilings and tall windows were designed to impress visiting generals, and they give a bedroom a sense of space a low modern ceiling cannot match.
Raffles assigns butlers to act as each guest’s guide to the building and the city. In a hotel this large, with this many corridors, that is less a flourish than a practical necessity.
Which room to book: Views are the variable worth paying for. Rooms facing Horse Guards or Whitehall carry the building’s sense of occasion; ask the hotel which categories have those outlooks before booking, as the official pages do not publish a full breakdown. Couples marking an occasion should look at the suites carved from former senior offices, where the Edwardian proportions are most generous.
Nine restaurants and three bars
The dining program is the hotel’s boldest decision. The flagship is Mauro Colagreco’s own restaurant. Colagreco made his name at the three-Michelin-starred Mirazur on the French Riviera, and his London dining room holds one Michelin star in the 2026 guide. The cooking is built on British produce, with more than 70 varieties of British fruit and vegetables in rotation and plant ingredients listed first on the menu. Mauro’s Table seats up to 20 around an open kitchen. Saison by Mauro Colagreco is the easier, all-day room, cooking Riviera-style Mediterranean food.
Elsewhere, Kioku by Endo serves Japanese-inspired cooking from the Michelin-starred chef Endo Kazutoshi on the sixth floor, with a terrace over the skyline. Paper Moon and Langosteria bring Milan to Whitehall, and Café Ciel runs a bakery-and-brunch residency by day. In The Drawing Room, afternoon tea is called Secrets & Spies, a nod to the building’s intelligence history.
The Spy Bar
The Spy Bar opens Tuesday to Saturday from 5 p.m. to 1 a.m. and has one house rule: no photographs. In a city where every new bar is built to be posted, a room that asks guests to put their phones away may be the most self-assured detail in the building.
The wine list carries the same idea of story. It is arranged by “British trade route” and “global trade route,” with a lean toward estates that farm sustainably.
The Guerlain Spa and Pillar Wellbeing
Central London hotels rarely do wellness at this scale. The Guerlain Spa has nine treatment rooms, a 20-meter indoor pool and a vitality pool, which the hotel calls a “cathedral of relaxation,” with hydrothermal facilities beside them. Pillar Wellbeing runs the gym and movement studio, with one-to-one coaching and its own juice bar, and Pillar Kitchen carries the approach into food.
Whitehall after dark
Whitehall is not a neighborhood in the usual sense. Horse Guards Parade, St James’s Park, Buckingham Palace, the Houses of Parliament and Westminster Abbey are all within walking distance, and Covent Garden and Soho are a few minutes further. Charing Cross and Waterloo stations are close, and Heathrow is about an hour by car. Once the ministries empty in the evening, the area is far quieter than the West End.
The OWO also sits inside a wider revival of ceremonial London. At the top of The Mall, Admiralty Arch is becoming a Waldorf Astoria, which we have covered in our Admiralty Arch guide. Between the two, a stretch of government London has turned into one of the more interesting places in the city to stay.
How it compares
London’s top tier now offers three distinct ideas of a grand hotel. Claridge’s is the inherited Mayfair icon. The Peninsula, at Hyde Park Corner, is the purpose-built modern palace with large rooms and a two-Michelin-starred rooftop restaurant. The OWO is the restoration on a heroic scale, with more places to eat and drink than either. It is the strongest choice for travelers who want history they can see in the architecture, and a hotel that is a destination after dark.
The trade-off is energy. With restaurants that draw large numbers of non-residents, the public spaces are busy by design. Anyone who prefers a small, hushed townhouse may find the scale and social buzz too much.
Who should stay
Raffles London at The OWO suits couples marking an occasion, first-time visitors who want Westminster on foot, food-led travelers who can plan a whole stay around its restaurants, and anyone hosting a large celebration: the Whitehall Ballroom seats 600 and is reached by the Grand Staircase.
Planning Your Stay at Raffles London at The OWO
Location: Whitehall, London SW1A 2BX, a short walk from Charing Cross and Waterloo.
Hotel style: Edwardian Baroque former War Office with 120 rooms and suites.
Best for: Celebrations, history lovers, food-focused city breaks, first-time London visitors.
Standout experiences: Mauro Colagreco, Kioku by Endo’s terrace, the Spy Bar, Secrets & Spies afternoon tea and the Guerlain Spa pool.
Reserve ahead: Mauro Colagreco and Mauro’s Table, afternoon tea, Kioku terrace tables in warm weather, and spa treatments.
Best time to visit: Year-round; the festive season pairs well with our guide to luxury Christmas hotel breaks.
Reservations: Through the official Raffles London website.
The Final Word
The OWO’s achievement is to turn a building designed to keep people out into one of London’s most sociable addresses, without losing the gravitas that made it matter. For travelers who want their hotel to be a destination in itself, it is hard to beat. For those who want quiet above all, London has calmer options.
This In-Depth Guide is based on the hotel’s official materials and independent reporting, verified October 18, 2026.
