Why did the London Underground get its own typeface?

The Underground got its own typeface because its commercial manager, Frank Pick, wanted a clear, distinctive look for the whole system. In 1913 he commissioned the calligrapher Edward Johnston as part of his plan to strengthen the company's corporate identity. Pick specified a typeface that would ensure that the Underground's posters would not be mistaken for advertisements, with the bold simplicity of the finest periods of lettering and a clearly twentieth-century character.

Johnston, regarded as a father of modern calligraphy with the broad-edged pen, did not copy the plain sans-serifs then popular. His capitals are based on Roman square capitals like those on Trajan's Column, and his lowercase on traditional serif fonts. Some parts are geometric: the O is a nearly perfect circle. The result is a sans-serif that keeps the proportions of Roman inscriptions and serif fonts, and his work is said to have originated the humanist sans-serif genre.

The design was first meant for printing, but it rapidly came to be used on the enamel station signs too. Johnston also worked on the bar and circle roundel that the Underground still uses.

Its life has been long. The typeface has been London public transport's corporate font since 1916 under predecessor companies, and since the London Passenger Transport Board was formed in 1933, which makes it one of the world's longest-lasting examples of corporate branding. A student of Johnston, Eric Gill, later used it as a model for his own Gill Sans.