“The road signs stand as symbols of modern Britain. Famous throughout the world, they represent the gold standard for highway directional signs. They adhere to Margaret’s observation that design is the ‘fusion of logic, function and aesthetics’,” says Adrian. “Their exceptional clarity and legibility – even at speed – along with their colour coding and use of symbols and pictograms to aid safety, make them one of the most significant contributions graphic designers have made to British public life.”

Margaret’s signage was designed to function at any time of day, utilising our natural understanding of colour theory – red for warnings and green for guidance and permission. In other photos from the book, exhibitions show cut-up signage, remixing the very concepts she created. Some signs here are seldom-seen, including pictograms of horse and cattle warning signs as well as multi-coloured speed limits and warnings against artificial intelligence. Created within European protocols for signage, Margaret made the best of triangles for warnings, circles for instructions and rectangles for information. It goes without saying that Margaret’s work was about pure functionality rather than creating something fashionable – these signs show how aesthetics can be don’t have to be plain to be utilitarian.

What’s more, Margaret designed transports and motorway typefaces, as well as signage for airports – and with Henrik Kubel she developed the Rail Alphabet 2 font, a lighter typographic voice than the signs from the 60s and more readable than the dark blue signs with reversed out type in the 2010s. Much of her work was created in the pre-digital era which Margaret designed laboriously by hand, using tools and techniques of the period. “It was me doing artwork on the table with a board and a T-square – and in the corner was the Grant enlarger, a machine for scaling type and images,” says Margaret in the book.

Beloved by so many graphic designers (and even being featured in a Top Gear interview), Margaret’s work will live on forever through these historically significant signs and typefaces that populate every side of the street in the UK – but this book is essential to understanding every piece of detail and love that went into something that we may take for granted these days. “Graphic designers value the signs because they demonstrate how design can tangibly improve the world. This is not branding for a packet of fish fingers – it is designed with life-and-death consequences,” says Adrian. As Robin Kinross has observed in Adrian’s introduction to the retrospective: “[Margaret’s] signs are a rare model of the role that design could play in public life.”