Drawing showing the standard layout of the 'Registered Design' version of the Johnston Underground bullseye (roundel)

This is the earliest known drawing of the Underground's standard bullseye design. It follows the 1916 version of the bullseye symbol created by Edward Johnston. The diagram shows Johnston's design guidelines for the symbol, including the exact proportions, measurements and colours to be used with the 'pecked' Underground lettering. At the bottom are the registered design numbers for two variations of the sign. The symbol was known as the roundel after 1972.