The landmark London building where British prime minister Winston Churchill worked during the Second World War is to be transformed into a luxury hotel and residence operated by Raffles; the group’s first property in the UK.

The Grade II* listed Old War Office building in Whitehall is located close to 10 Downing Street, the Houses of Parliament and Westminster Abbey. It was designed by Scottish architect William Young before his death in 1900 and completed by his son, Clyde Francis, six years later.

Many of the country’s most important and influential twentieth century political and military leaders worked there, including David Lloyd George, Lord Kitchener, Herbert Asquith and T.E. Lawrence.

The British Secret Service also occupied some of the building’s 1,100 rooms – which are spread across seven floors and two miles of corridors.

Indian investment firm the Hinduja Group and Spanish construction company Obrascon Huarte Lain Desarrollo bought the building in December 2014 after submitting a public bid. They have been granted planning permission to adapt the interiors to house 125 hotel rooms, of which 40 per cent are suites, 88 private residences, restaurants and other amenities. Completion is expected by 2020.

The first Raffles Hotel was opened in 1887 in Singapore and named after the British statesman and founder of Singapore, Sir Thomas Stamford Raffles.

Explaining the decision to bring in the company to operate the new London hotel, Hinduja Group Co-Chair Gopichand P. Hinduja said it would “bring a unique understanding of British heritage and tradition that will help revive this great British landmark.”

He adsded that the partnership is “a significant milestone in our vision to transform the Old War Office into London’s finest luxury destination.”

Sébastien Bazin, Chair and CEO of Raffles’ parent company AccorHotels added: “This is the start of an important partnership and will create a new and vibrant landmark for London. This is a significant step for Raffles and a strategic addition to the Group’s luxury portfolio. We remain committed to providing guests with unparalleled service and experience.”