Shalini Hinduja has an enviable problem. She has some new homes to sell — 85, in fact — and she has no idea what wildly high price to charge for them. She knows that they will start at about $7 million for a two-bedroom apartment of up to 3,000 sq ft. But what about the vast three-bedroom homes or the duplex penthouses that have some of the best views in London and a history as rich as that of any home in the world? $50 million? $100 million? $150 million? More? “It’s like selling artwork,” she says.

Hinduja, the daughter-in-law of Gopichand Hinduja, who with his brother, Srichand, runs a global trading conglomerate that has earned them a $24 billion fortune that puts them third on the Sunday Times Rich List, is creating homes at one of the greatest addresses in London: the Old War Office (OWO), opposite Horse Guards on Whitehall.

Just Next Door to Raffles …

You’ve seen it before. In the final scene of Skyfall, James Bond, played by Daniel Craig, stands alone looking out over the roof of the building across the London skyline before Moneypenny hands him a gift from the late “M”. Ian Fleming, Bond’s creator, developed 007’s character in the Old War Office, where he worked during the Second World War, liaising between naval intelligence and MI6.

Daniel Craig as James Bond in Skyfall.

Winston Churchill, T E Lawrence (of Arabia), and Lord “Your Country Needs You” Kitchener also worked in the building’s oak paneled rooms. Churchill served as secretary of state for war from 1919-21. His old office, which can be used by residents for meetings and private dinners, has a copy of the Mountbatten desk he worked at before he moved across the road to Downing Street.

The 85 apartments retain many of the building’s original features and will adjoin Raffles London: the British debut of the Singapore-based hotel group takes up the other half of the building. The prime hotel suite, reached via the grand Whitehall entrance and vast marble staircase, will be the Churchill, formally known as the Haldane, with views over Horse Guards. Also popular will be the former Army Council Room suite, once used by chiefs of staff for meetings.

A home office in one of the turrets, which were previously reserved for use by members of Britain’s Army Council.

The flats are certain to attract some of the wealthiest buyers in the world. And that’s where things get tricky for Hinduja.

The super-prime London housing market has gone crazy, even by its razzle-dazzle standards. The property developer Nick Candy recently put his penthouse in One Hyde Park on the market for $247 million. If a glitzy glass box for new money barons is worth that much, how do you price a building that, as Hinduja puts it, “vibrates with memories”?

After residents come in through the “Spies entrance,” on Whitehall Court, the sprawling marble staircase awaits.

Residents will enter the grade II listed OWO — pronounced Oh-woe — via the “Spies entrance” on Whitehall Court, formerly reserved for Fleming and his fellow spooks. MI6’s original headquarters was across the road, disguised as the offices of Rasen, Falcon & Co Shippers and Exporters. They will head up once-secret stairways or clanking lifts to vast apartments with ceilings up to 15ft high, original mosaic floors and, for the lucky few, hexagonal turrets looking out over London. These turrets, at each corner of the building, were previously reserved for use by members of Britain’s Army Council — our top brass.

Everywhere you go there are thrilling nods to the past. Clocks on the wall still show the time in major capital cities. The restored chandeliers are based on those at Hampton Court and many of the marble fireplaces came from Cumberland House and Buckingham House on Pall Mall. It was in a nondescript basement room that George Blake, the infamous double agent, was — unsuccessfully — interrogated by his handlers.

The super-prime London housing market has gone crazy, even by its razzle-dazzle standards.

Each apartment has a unique shape and layout but they all have full-height doors and the glass in the windows is bomb-proof — this is the Old War Office, after all. The kitchens, designed by Smallbone of Devizes, are dark-stained walnut with brass fittings. The floors in all the main rooms are herringbone pattern oak. The bathrooms are gray onyx and polished marble with brass detailing.

The walnut-and-brass kitchens were designed by Smallbone of Devizes.

The entrance to some apartments fills what once was a full corridor of the old building, and inside, the corridor forms the walkway dividing the two halves of the flat. There are — or were — two and a half miles of 10ft-wide corridors in the building. Boy scouts used to cycle around them delivering messages to the 1,100 offices. The scouts’ Messenger Rooms have been preserved in the apartments as studies — the ultimate place to WFH.

Most homes look out over the city and the central quadrangle. The upper three floors — the 5th to the 8th, which are new-build, topped off in Portland stone — have private gardens and terraces. Residents without outside space can use the private garden near the quadrangle. All the renovations, overseen by the architectural firm EPR led by Scott Paton, the developer OHL Desarrollos, based in Madrid, and the apartment designer 1508 London, were agreed with Historic England.

Churchill worked in the Haldane suite.

Private lifts will take residents down to the lower floors, which were once a warren of tunnels connecting a huge communications exchange, an all-night canteen and bomb shelters where workers sat out the Blitz. In their place are a more comfortable but less thrilling spa, gym, pool, cinema and library.

Raffles staff will service the flats, offering everything from butlers to nutritionists. Owners will also be able to enjoy the rooms, restaurants and bars in the hotel, whose interiors are designed by New York-based Thierry Despont.

What—No Cigar Lounge?!

The Scottish architect William Young began designing the Old War Office in 1898 and his son Clyde took over the project when William died in 1900. The building took five years to build and cost $1.7 million at the time. Some 2,300 officials worked there but during the First World War so many more staff were needed that wooden huts were installed on top of the building to house an additional 550. The part of the roof on which the huts stood was macabrely nicknamed the “Zeppelin Terrace”.

The government put the building up for sale a decade ago as part of a $7 billion Whitehall cost-cutting program. The Hinduja Group conglomerate bought it on a 250-year lease in 2014 for a reported $494 million.

That sounds cheap, I suggest to Shalini Hinduja when she shows me around the building. “I’m not a finance person,” she says, not quite swerving the issue. “It wasn’t the highest bid. It was the fourth highest. There were a lot of other things that went into consideration of what would be best for the project.” Like what? “Passion.”

The Old War Office, as seen from Horse Guards Avenue.

That she has in spades. She got the bug for breathing new life into the old after she and other family members did up four John Nash grade I listed houses, now worth $113 million each, on Carlton House Terrace. She and her husband, Dheeraj, and the extended Hinduja clan now live in them. The houses had been owned by the government and served as offices and homes for prime ministers, including William Gladstone.

Transforming the OWO will, Hinduja says, give something back to a city “that has given us so much. The family feels strongly about leaving a legacy.” Shalini Hinduja was born in India but grew up in London and studied at University College London and Imperial College.

Fine, but isn’t Britain selling the family silver? Does such an important building really need to be another glitzy hotel and homes for the global super-rich, like, er, the Hindujas? “This was a building that wasn’t being used. It had been closed. We’re giving it new life, purposeful life. It’s a rebirth.”

She emphasises that the hotel will be open to the public and there will be tours of the historic suites ten days a year. “We want to share it with everyone.” Hinduja is also building “a memorial room”, to showcase the building’s history with archive photographs lent by the Imperial War Museum.

In fact, in her quest to revive an icon, there’s only one thing she has forgotten. There is — gasp! — no cigar lounge. What would Churchill say? The Old War Office has appeared in more James Bond films than any other building. It features as MI6 HQ in Octopussy (1983), A View to a Kill (1985) and Licence to Kill (1989). The final scene of Skyfall (2012) was filmed there, as was the final scene of Spectre (2015), when Bond and the psychiatrist Dr Madeleine Swann drive off in a vintage Aston Martin. In 1961 the War Office wrote to the Bond filmmakers to say that it could not loan or sell flame-throwers for use in Dr No “as these are prohibited weapons.”

John Arlidge covers business for The Times of London