The government has bought a $15.9m (£12m) seven bedroom luxury New York apartment for a senior British civil servant charged with signing fresh trade deals in a post-Brexit world, the Guardian can reveal.

The foreign secretary Jeremy Hunt oversaw the purchase of a 5,893 sq ft (574 sq metre) apartment as the official residence for Antony Phillipson, the UK trade commissioner for North America and consul general in New York. The apartment occupies the whole of the 38th floor of 50 United Nations Plaza, a 42-storey luxury tower near the UN headquarters in Manhattan.

The 167 metre tower, designed by the firm of celebrated British architect Norman Foster is described as “the ultimate global address”, and was also home to Nikki Haley when she served as the US ambassador to the UN until December 2018.

A bedroom in the apartment in 50 United Nations Plaza. Photograph: PR Image

The apartment, which is called Penthouse 38, boasts a 73.6ft by 21.3ft living area complete with a dining room, living room and library. Chefs will be able to whip up a feast in the kitchen, which features both a double oven and a “speed oven”, as well as two dishwashers, an icemaker and wine cooler.

New York City records seen by the Guardian show that “Her Britannic Majesty’s Secretary of State for Foreign and Commonwealth Affairs” bought the apartment for $15,900,000 (£12m) on 15 March.

A spokesman for the FCO said: “We have secured the best possible deal and value for money on a property that will help promote the UK in the commercial capital of our largest export market and trading partner.

“As well as being the consul general’s residence, it will also be used to support his work to help British businesses as Her Majesty’s Trade Commissioner for North America. We are in the process of selling the consul general’s current residence.”

50 United Nations Plaza floor plan Photograph: PR

The apartment was bought from the tower’s developers – the super-rich Zeckendorf family and Eyal Ofer, a Monaco-based Israeli real estate tycoon with an estimated $10.5bn personal fortune that makes him the 132nd richest person on the planet.

The apartment features five large ensuite bedrooms, as well as two further rooms labelled “staff bedrooms” on the floorplan.

One of the staff rooms works out at 6.3 sq metres – only slightly larger than the minimum legal size of a prison cell. One of the apartment’s three walk-in wardrobes is larger than both the staff rooms.

The ensuite bathroom comes complete with a freestanding French marble bathtub. Photograph: PR Image

The master bedroom is 6.6 times larger than the staff room at 42 sq metres, not including the ensuite bathroom, which comes complete with a freestanding French marble bathtub in the window overlooking the New York skyline, as well as a separate shower and steam room.

The Guardian understands the staff rooms will be removed and Phillipson will not have live-in staff.

Living next door to the UN headquarters, Phillipson will be in prime position to wine and dine dignitaries from around the world to encourage countries to sign fresh trade pacts with Britain in the event of the UK’s departure from the European Union.

Phillipson, who joined the civil service in 1993, served as director of trade and partnerships in Department for Exiting the European Union (DExEU) until November 2017 when he moved to New York.

The developer of the tower boasts that a “stroke of genius” allowed the creation of a 75-metre black marble-lined swimming pool, which is 50% longer than an Olympic-standard pool and promises a “new level of aquatic extravagance” in “the most glamorous pool in Manhattan”. Nearby is a “temple of wellness” with fitness centre, steam room and sauna.

50 United Nations Plaza’s black marble-lined swimming pool. Photograph: PR Image

The building, which is known by locals as 50UNP, also promises its residents “an extraordinary level of privacy, security and serenity”. There is a 24-hour gated-security entrance and residents-only valet parking.

A spokesman for Zeckendorf Development and Ofer’s Global Holdings Inc said: “We are delighted with this full floor penthouse sale to Her Britannic Majesty’s Secretary of State for Foreign and Commonwealth Affairs of the United Kingdom of Great Britain and Northern Ireland, and thrilled that 50 United Nations Plaza is now over 83% sold.” The NYC department of finance office of the city register filing for the apartment sale was covered by NY property website The Real Deal.

The Qatari government bought four apartments in the 50 United Nations Plaza tower for $45m in 2015. Brochures for the building describe luxury including “vast expanses of glass, warm gold bands and stainless steel detailing distinguish this new architectural statement for the city – always at home in the world”.

Enjoying the holidays with sweet friends...#TisTheSeason pic.twitter.com/sehd3IV4BH — Archive: Ambassador Nikki Haley (@AmbNikkiHaley) December 24, 2017

“Global architects Foster + Partners have custom-designed every detail of 88 spectacular condominium residences,” the advertising states. “The quality of space, light and views is unprecedented, creating the truest sense of arrival and the modern and timeless luxury of New York living.”

Foster + Partners said: “Every apartment is focused on the series of floor-to-ceiling bay windows and the interiors are luxurious, with generous space for entertaining. Adding a touch of elegance to every detail, the powder room walls are fitted with glazed silk panels in a choice of either bold primary or natural colours.

“A spa in the basement incorporates a large exercise pool for residents, and the penthouse features an infinity pool, dramatically cut out from the top level of the building.”

The FCO is also spending £55m refurbishing the British embassy in Washington DC. The repair and refurbishment project includes the 6,000 sq metre Ambassador’s Residence, the 2,000 sq metre Old Chancery Building, and the more modern 10,000 sq metre New Chancery Building.