The Old War Office in Whitehall, SW1, will be converted into 85 flats and a hotel by the Hinduja brothers.
The seven-floor, Grade II listed gothic building, completed in 1906, was bought in 2014 for £350m by the Hinduja Group, owned by the brothers Gopichand and Srichand Hinduja, whose family wealth exceeds £17bn.
Knight Frank has begun marketing the apartments, which start at £5.8m. The hotel will be run by the Singaporean luxury chain Raffles.
