1863-1908
Prior to the unification of branding in 1908, each individual operating company had its own branding and logo. Thus there was no definitive 'London Underground' logo during this period.
1908-1913
In 1908, the individual companies operating the London Underground at the time agreed upon a unified branding design, the central element being the then new 'Underground' name and logo.
1913-1919
1919-1933
Due to the technical restrictions of the time, this roundel could be seen in various dimensions depending on its application.
1933
The letters LPTB (London Passenger Transport Board) were added to the roundel in 1933.
1933-1949
The words 'London Transport' were added onto the roundel in 1933.
1949-1951
In 1949 "London Transport" was removed from the logo, and the name was changed to "RAILWAYS".
1951-1958
In 1951, the outlining was removed.
1958-1969
1969-1972
In 1969, the letters were changed to be uniform in height.
1972-1986
1986-present
In 1986, the traditional red and blue roundel was brought back into use. This time it has been modified so the circle and bar strokes are the same width. The colours have also been brightened.