Airports, road signs, animal warnings … Margaret Calvert revolutionised how Britain looked and her brilliantly clear designs are still used today. We meet the font legend and Porsche lover

Stuffed with a barrage of road signs, artful modernist chairs and all the tools of her trade, Margaret Calvert’s studio occupies the ground floor of her trim terrace house in Islington, London. She still draws by hand, using coloured pencils, ink pens and gouaches, echoes of a simpler time when there were neither computers nor gazillions of Pantone colour options. “There was also no such thing as graphic design back then,” she says. “It was just called commercial art.”

Only a handful of graphic designers have had a typeface named after them. One of the earliest was the 18th-century Italian Giambattista Bodoni, whose fonts have conferred on him a kind of immortality. But his efforts were not to everyone’s taste: William Morris was said to have loathed Bodoni’s letters, grumpily raging at their “sweltering hideousness”.