The capital M from Gill Sans is based on the proportions of a square with the middle strokes meeting at the centre of that square. The Gill Sans typeface family contains fourteen styles and has less of a mechanical feel than geometric sans-serifs like Futura, because its proportions stemmed from Roman tradition. Unlike realist sans-serif typefaces including Akzidenz Grotesk and Univers the lower case is modelled on the lowercase Carolingian script. The Carolingian influence is noticeable in the two-story lowercase a, and g. The lowercase t is similar to old-style serifs in its proportion and oblique terminus of the vertical stroke. Following the humanist model the lowercase italic a becomes single story. The italic e is highly calligraphic, and the lowercase p has a vestigial calligraphic tail reminiscent of the italics of Caslon and Baskerville. Gill Sans serves as a model for several later humanist sans-serif typefaces including Syntax and FF Scala Sans. An Infant variety of the typeface with single-story versions of the letters a and g also exists.
The basic glyph shapes do not look consistently across font weights and widths, especially in Extra Bold and Ultra Bold weights, and Extra Condensed width. However, even in lighter weights, some letters do not look consistent. For example, in letters p and q, the top strokes of counters do not touch the top of the stems in Light, Bold, Heavy fonts, but touch the top of the stems in Book, Medium fonts.
Gill Sans Schoolbook is released in TrueType, PostScript Type 1 format. Gill Sans Infant is released in OpenType CFF format, supporting ISO-Adobe 2 character set, super and subscript OpenType features.
The type is based on the Arabic Naskh style with a modern look that echoes the proportions and feel of Gill Sans.
First unveiled in a single uppercase weight in 1928, Gill Sans achieved national prominence almost immediately, when it was chosen the following year to become the standard typeface for the LNER railway system, soon appearing on every facet of the company's identity, from locomotive nameplates and station signage to restaurant car menus, printed timetables and advertising posters — roles it took on nationwide for British Railways after nationalisation in 1948, until the comprehensive British Rail corporate rebranding in 1965 which used the especially designed Rail Alphabet. Other users were quick to follow, including Penguin Books' iconic paperback jacket designs from 1935, and Gill Sans became Monotype's fifth best selling typeface of the twentieth century.
The typeface continues to thrive to this day, often being held to bring an artistic or cultural sensibility to an organisation's corporate style. Prominent users include the BBC, which adopted the typeface as its corporate typeface in 1997. Until 2006, the corporation used the font in all of its media output; however, the unveiling of its new idents for BBC One and BBC Two has signalled a shift away from its universal use, as other fonts were used for their respective on-screen identities.
Other organisations using Gill Sans include: