Coordinates: 51°29′43.03″N 0°10′6.93″W / 51.4952861°N 0.1685917°W
Mortimer House is a large detached house on Egerton Gardens in the South Kensington district of London SW3. The house occupies a large corner plot on the corner of Egerton Gardens and the Brompton Road.
The site had been formally occupied by Crescent House, which had been inhabited by the former Governor of the Bank of England Edward Howley Palmer, since 1881. In the mid 1880s the trustees of the Smith's Charity estate, the local freeholders, agreed to Palmer's decision to rebuild the property. Palmer agreed with the trustees to pay a ground rent of £100 for the first year and £240 annually subsequently. The house was built by the Hatton Garden builder William Goodwin. It is not known who designed the house, nor why it was named Mortimer House.
Palmer had recently commissioned architect Richard Norman Shaw to design a house on Cadogan Square for him, but did not occupy it, and Palmer was last listed as the occupier of Mortimer House in 1892. Palmer sold the house in 1896. A Charles Sheridan Swan owned Mortimer House in the early 20th-century, his widow, Mary Kelly Swan, died there in 1909. The house was later sold in May 1913.
Mortimer House was owned by the chairman of British American Tobacco, Sir Frederick Macnaghten, in the 1950s and 1960s. His widow, Dame Ada, died there in 1969. The gardens of Mortimer House were open to the public in 1965 as part of the National Gardens Scheme. They were described by The Times as featuring "...an attractive display of roses and a rock garden".