London Underground’s red-and-blue circular logo is called the roundel.
The familiar design consists of a red circle or bar set across a blue horizontal rectangle or ring, with the station name displayed prominently. It became a powerful wayfinding device because passengers could recognise it from a distance, even when station architecture differed from place to place.
The roundel developed from earlier railway signage and was standardised as part of the Underground’s broader design programme. Frank Pick, a leading Underground manager, encouraged consistent visual communication across stations, trains, maps, posters and signs. Edward Johnston’s typeface, introduced for Underground use in 1916, helped make the sign’s lettering equally distinctive.
The logo is often casually called the “Underground logo,” but “roundel” is the specific design term. London buses and other Transport for London services use related roundel forms, sometimes with different colours. The symbol’s success comes from combining a simple geometric shape with highly legible signage rather than relying on a complex emblem.