Discover the interior of the new Raffles hotel in London.

The Old War Office in Whitehall, London, exudes a rich history, having once been Winston Churchill's workplace.

The former headquarters of Britain's military empire, where significant decisions in modern U.K. history were made, is now being transformed into one of London's top luxury hotels, Raffles London.

The Grade II* listed Edwardian Baroque building, situated near Downing Street and the Palace of Whitehall, has undergone an eight-year renovation and is now the first European location of the renowned Singaporean brand.

Fiona Harris, communications director of Raffles London, revealed to CNBC Travel that the hotel's success is due to the perfect blend of its architecture, location, and name.

The Raffles brand has completed a full circle with the hotel's recent opening, honoring Sir Stamford Raffles, the British diplomat who founded modern Singapore.

The Hinduja Group, which acquired a 250-year lease from the Ministry of Defense in 2016 and traces its roots back to a trading company established in colonial India in 1914, has evolved into a global conglomerate.

The £1.4 billion ($1.7 billion) redevelopment of the former control center of the British empire is now a luxury stable for international visitors to the U.K.

An emblem of British history

The OWO building, constructed for the British Army from 1899 to 1906, symbolized imperial power at its peak.

Over 2,500 British military personnel were stationed in the building's 1,100 rooms and two-and-a-half miles of hallways.

The grandeur of the building remains today under extensive renovation by EPR Architects, with much of its original features being restored.

The grand lobby boasts an Italian marble imperial staircase and a double-tier chandelier, reflecting the building's history as the birthplace of the British Secret Service and the inspiration for Ian Fleming's James Bond series.

The balcony on the first floor was where Churchill would speak to his staff, and it was later used as offices by notable political and military figures such as David Lloyd George and Lord Kitchener.

"If this building had been filled with state secrets, it would have been a hub of government information," Harris remarked.

The former prime minister's office, now a suite, retains its grandeur with a replica desk and bust.

Pivot to the future

The Churchill suite is one of the rooms renovated in honor of the building's history by the late Thierry Despont, who is known for his architectural achievements, such as restoring New York's Statue of Liberty and redesigning the interior of Manhattan's residential skyscraper 220 Central Park South.

The hotel has 120 suites and rooms, including five heritage suites in the ex-offices of political and military leaders, and eight corner suites named after famous women and female spies.

An underground excavation of three floors has increased the building's area by more than a third to 800,000 square feet, creating a ballroom, a 65-foot swimming pool, and a Guerlain spa.

Nine new restaurants, three of which are run by multi-Michelin star chefs, including three by Argentina’s Mauro Colagreco, aim to enhance the hotel’s reputation as a culinary hub in the city. Additionally, three new bars will highlight the hotel’s unique history and location.

At the Guards Bar and Lounge, guests can watch the famous changing of the guard ceremony while sipping on a London Sling, a gin and cherry cocktail inspired by its Singapore namesake.

Those looking for a more discreet experience can visit the subterranean spy bar, which is located in an old interrogation room, and pay tribute to the many spies whose secrets were kept there.

The Ministry of Defense's lease agreement allows for 11 annual open days for non-paying guests to visit and tour the building.

"The building that previously required security clearance for entry is now open to all, regardless of wealth or reason for visit, as Harris stated," she said.

London’s new luxury wave

Staying at Raffles London comes with a hefty price tag. The cost of a classic room is approximately £1,100 ($1,340) per night, while the five most exclusive suites range from £18,000 to £25,000 per night.

Individuals who wish to remain in the property forever can purchase one of the 85 Raffles branded OWO residences, which costs over £8 million. Currently, approximately half of these units have been sold to buyers from various countries, including the U.S., China, and the Middle East. However, a five-bedroom penthouse priced at £100 million is still available for purchase.

Despite Britain's economy and population facing financial strain due to high inflation, Raffles is not the only one to invest heavily in London's luxury market.

In the upcoming months, London will see the launch of four luxury hotels: The Peninsula, Mandarin Oriental, Rosewood, and The Emory.

Gopichand Hinduja, Hinduja Group Chairman and OWO's owner, stated that the investment in the property in 2016, prior to the Brexit downturn, demonstrated Britain's enduring allure as a luxury travel destination.

Hinduja stated in July that the U.K. is significant and attracts many visitors, whether for leisure or business purposes, and they do not focus on short-term trips.

Hinduja stated that The OWO building has been transformed into a peaceful and serene environment. This distinctive property is a must-visit destination.