London Underground first introduced its circular red-and-blue roundel symbol in 1908.
The roundel developed from an earlier horizontal bar-and-circle design used to make station names easier to identify. The red ring and blue bar created a strong, simple sign that passengers could recognise quickly in crowded streets and station interiors.
The symbol became central to London Underground’s visual identity. It later appeared on station signage, posters, maps, vehicles and publicity. Its clarity also made it adaptable: the bar could carry a station name, while the circular form remained recognisable from a distance.
The roundel is sometimes confused with the Johnston typeface, another major part of the Underground’s branding. Johnston was commissioned later and introduced in 1916. The roundel and typeface work together, but they were separate developments with different dates and functions.