In his book, Artwork, published by Ebury Press, David Gentleman writes of his admiration for artisanal marks made by craftsmen, printers and publishers. These symbols, he says, were emblems that grew out of the workplace, unlike the fanciful winged lions and unicorns of heraldic imagery.

In 1969 Gentleman was asked to design a symbol for the newly nationalised steel industry.

To get at the core of the steel-making process, he became interested in the steel samples that were originally made to show how the metal performed under stress. “When bent double,” he writes, “the best steel wouldn’t crack.” Taking the concept to its logical conclusion, he drew two concentric circles then halved, separated and joined them up via four lines. The simple geometry of this ‘S’ – it has the same proportions as A4 – meant it could easily reproduce at any scale, in a positive or negative form.

While the logo was designed to appear in both black or white on backgrounds of various colours, the symbol itself could only ever be rendered in one other hue: Pacific Blue (bs0-012). “It’s the epitome of pure modernist graphic design,” says Mike Dempsey, “maximum effect employing the minimum of elements. It is witty, distinctive, memorable and over four decades on it still looks fresh and beautiful.” The logo was in use for 20 years until the corporation was re-privatised as Corus.

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