This summer, an awful lot of purple will be evident in London, from regal jubilees to the opening of the Elizabeth line, and not many people know that the modern colour purple was invented in London.

Purple had been around for millennia, but it cost a literal King’s ransom to manufacture it, as a useable purple dye was only produced by a type of sea snail and it required thousands of snails to make a single cloak. So expensive was the colour that it was often limited to Kings and Emperors, and at times it was even illegal for anyone else to wear the colour purple.

But, in 1856, a young London chemist invented the world’s first artificial purple dye that was so bright and so cheap that it was to dominate London fashion for many years, and the technique was to spur an entirely new avenue for chemists to explore.

The hero in our story is William Henry Perkin, born in 1838 as the son of a carpenter, and although the youngest of seven children, his father was wise, and presumably modestly wealthy as he sent young William to school where he learnt chemistry.

Aged 15, he joined the Royal College of Chemistry and studied under the German chemist, August Wilhelm von Hofmann, who was a leading light in researching organic chemistry. Hofmann had a theory that it might be possible to use aniline extracted from coal tar to synthesise quinine, an expensive substance extracted from the bark of a Peruvian tree that was a critical element in treating malaria in the British Empire. The British taste for gin and tonic owes a lot to the addition of quinine to tonic water.

But back then, quinine was expensive, and synthetic quinine would help save a lot of lives by reducing the cost, so Hofmann gave the task of carrying out the research to his student, William Perkin.

It was in a crude laboratory in his bedroom, at the top floor of a house in Cable Street, Shadwell, that William tried out some experiments with aniline when he found that when it was extracted with alcohol, could produce a powder that had an intense purple colour.

This was technically a failure – they wanted quinine but they had purple powder.

Unlike Lord Percy, William was both clever and an artist, and immediately realised the importance of what he had stumbled upon, and working with a friend Arthur Church and his brother Thomas, the trio worked on improving the discovery and having assured themselves that production could be scaled up to commercial levels, sent samples of purple fabrics to a dye works, and filed for a patent on the discovery.

He now had not only a colour dye that would be hugely desirable, it was made by a simple chemical process using a cheap by-product of the process for making coal gas and coke.

William was just 18 years old and he had an invention that would change the world.

Raising money from investors, including his own father, he was able to set up a factory in Greenford and in late 1857, launched Aniline Purple on an unsuspecting public. It was renamed Mauve in 1859, which sounded better, and for the next few years, it was the most desirable colour for ladies of fashion to be seen wearing. It’s not without good reason that many of our images of Victorian fashions contain an abundance of richly coloured fabrics. In fact, so prevalent was the use of purple, that in August 1859, Punch magazine described society as suffering from an outbreak of the “Mauve Measles”.

It was a short-lived mania as it became a victim of its own success.

The idea that coloured dyes could be synthesised from coal tar spurred other people to experiment, and to the invention of the wider synthetic dye industry. Fickle fashion moved on.

But for a few years, London was awash with the colour purple, and all thanks to a young man making a mistake.

William Perkin did well out of his invention and was wise enough to reinvest his profits in more research, inventing more synthetic colours, bright violets and greens.  Local legend had it that the colour of the nearby Grand Union Canal changed from week to week depending on the activity at Perkin’s Greenford dyeworks.

Apart from his legacy in coloured dyes and chemistry, he was knighted, lauded, and oft-times applauded in life. In death, he has two plaques, on the site of his Cable Street home and the Greenford factory, and the nearby school is called the William Perkin High School, and unsurprisingly, the colour purple is used for its logo and school uniform.

So when you see lots of purple across London this summer, remember, it was invented here as well.