Colour standards, initially for specification purposes (e.g., the Post Office, Railways, and the Military), were transformed in Britain during the 1970s into instruments for the pursuit of a Modernist agenda. Extolling a rational approach to colour, a master standard and a set of derived standards were devised at the British Standards Institution that would provide a colour palette covering the entire built environment of Britain. These revolutionized colour standards and were a unique venture in any country. This article charts the development of these standards, the problems to be overcome, and the role of their originators, Gloag, Hardy, and Medd. These little known figures had-and continue to have-a unique influence upon the colour of the built environment. Literally, they coloured Britain. And their standards remain in force today. (C) 2013 Wiley Periodicals, Inc.