The house flag of Constants Ltd, London. A red rectangular flag bearing a white disc in the centre with a black letter 'C' on it. The flag is made of a wool and synthetic fibre bunting. It has a cotton hoist and is machine sewn. A rope and toggle is attached. The hoist is inscribed 'Constants Cardiff'.

The Constant family had been Thames ship owners since the 18th century with a head office in London during the 20th century. Constants (South Wales Ltd) was formed in 1929 with an office in Cardiff. Its fleet of tramps exported coal from South Wales and imported iron ore from Northern Spain, cork, pyrites and timber from Portugal and other cargoes from the Mediterranean. The company was wound up after the war and its ships registered under the London office. During the 1950s and 1960s, a small modern fleet tramped worldwide. In 1973 the family sold the company to Dovey Shipping and Industrial Holdings Ltd, Cardiff who closed the business down in 1976.