The house flag of Houston Line Ltd, London. A union flag with a white border and the cross of St George extending to the outer edges. In the centre, is a white disc with the red letter 'H'. The flag is made of a wool and synthetic fibre bunting. It has a cotton hoist and is machine sewn. A rope is attached.

The Houston Line was formed in 1880 in Liverpool as R.P. Houston and Company. The ships originally carried frozen meat from Argentina to the United Kingdom. Passenger service started five years later. In 1898 the company became a subsidiary of the newly formed British and South American Steam Navigation Company. The company shortly began running services from New York to Argentina, as well as a United Kingdom to South Africa route. This route was short-lived, however, and halted in 1904 when the Union Castle Line made an agreement with the company to purchase one of its ships if it stopped the service. In 1918 the company was sold to the Clan Line; however the ships still operated under the name R.P. Houston. In 1926 the company’s South American services were sold to the Royal Mail Group, and in 1932 the line’s name was officially changed to the Houston Line. In 1956, the British and Commonwealth Shipping Company was formed, combining the Houston Line, Clan Line, Union Castle Line, Bullard King and King Line. The following year, Houston Line and Bullard King began operating a joint service to South and East Africa. The subsidiary stopped operating as the Houston Line in 1970. (Research: Rebecca Hernandez).