The High Commissioner was originally domiciled in a government bungalow, Four Furlongs, on Bauddhaloka Mawatha (formerly Bullers Road) in Cinnamon Gardens.

[1] In the late 1990s the British Government decided that the existing office of the High Commission was no longer fit for purpose and acquired a 0.8 ha (2.0 acres) site on Bauddhaloka Mawatha, from the Meteorological Department, adjacent to Westminster House.

[2] In 2001 the Scottish architectural practice, Richard Murphy Associates, in collaboration with local architect, Milroy Perera, was commissioned to design the new offices.

The single-storey building has a central spine traversing the middle of the site with four wings leading off it on either side in a staggered arrangement, creating a series of small intimate courtyards, reflecting aspects of traditional Sri Lankan architecture.

[2] On 14 November 2013, King Charles celebrated his 65th birthday at Westminster House, whilst he was attending the 23rd Commonwealth Heads of Government Meeting in Sri Lanka as the Prince of Wales.