Underground roundel at Baker Street Station, London, England

From Wikipedia:

Roundel in Euston Square tube station. The ring was introduced by Frank Pick before he commissioned Edward Johnston to develop the final version of the symbol.
While the first use of a roundel in a London transport context was the trademark of the London General Omnibus Company registered in 1905, it was first used on the Underground in 1908 when the Underground Electric Railways Company of London (UERL) placed a solid red circle behind station nameboards on platforms to highlight the name. The word “UNDERGROUND” was placed in a roundel instead of a station name on posters in 1912 by Charles Sharland and Alfred France, as well as on undated and possibly earlier posters from the same period.

Transport administrator Frank Pick, wanting to establish a strong corporate identity and visual brand for the Underground, thought the solid red disc cumbersome and took a version where the disc became a ring from a 1915 Sharland poster and gave it to Edward Johnston to develop, and registered the symbol as a trademark in 1917. The roundel was first printed on a map cover using the Johnston typeface in June 1919, and printed in colour the following October.

After the UERL was absorbed into the London Passenger Transport Board in 1933, it used forms of the roundel for buses, trams and coaches, as well as the Underground. The words “London Transport” were added inside the ring, above and below the bar. The Carr-Edwards report, published in 1938 as possibly the first attempt at a graphics standards manual, introduced stricter guidelines. Between 1948 and 1957 the word “Underground” in the bar was replaced by “London Transport”. As of 2013, forms of the roundel, with differing colours for the ring and bar, are used for other TfL services, such as London Buses, Tramlink, London Overground, London River Services and Docklands Light Railway. The Elizabeth line is identified with a purple roundel. The 100th anniversary of the roundel was celebrated in 2008 by TfL commissioning 100 artists to produce works that celebrate the design. Roundels are featured outside many underground stations; they are commonly mounted on a white pole known as a “Venetian mast”.

In 2016, Tate Modern commissioned conceptual artist Michael Craig-Martin to “reimagine” the roundel, changing its colours for the first time since the sign was introduced. His design was displayed at Southwark Station in collaboration with Art on the Underground to mark the opening weekend of the new Tate Modern gallery situated near the station.

Image Details
Date: 9 December 2025
Camera body: Nikon D50
Lens: Nikkor AF-S DX 18-55mm ƒ3.5-5.6G ED
Focal Length: 55mm
Aperture: ƒ/5.6
Shutter Speed: 1/25s
ISO: 800
Licence: Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International