Johnston or Johnston sans is the typeface widely used by Transport for London for its publicity material and signage across the whole of its activities. The typeface was commissioned by the London Electric Railway in 1913 as part of a drive to strengthen the company's corporate branding and replaced a variety of typefaces used across its services. The font was originally simply called "Underground" but is now named after its designer, Edward Johnston, who also designed the London Underground roundel. The use of the typeface survived the merger of the LER into London Transport and spread to be used across the entire system.

Intended for posters and signage, Johnston's design originally consisted of just capital letters, numbers and punctuation symbols but the widening of its usage saw the addition of lower case characters and different type weights. The typeface is sans-serif and features a perfectly circular capital letter O and diamond-shaped full-stop and dots over the letters i and j. The current version of Johnston in use was designed to be slightly heavier than the original and is named New Johnston. (Full article...)