Priya Anand, 28, has shaved her underarms every four to five days without pause since she was thirteen, a routine she realised only this month she began in direct and unbroken continuation of a marketing campaign Gillette launched in 1915.

That campaign introduced the Milady Décolleté, the first razor marketed specifically to women, timed to a fashion shift toward sleeveless dresses and run alongside advertising that described underarm hair as "unsightly" and something "women of fashion" would naturally wish to remove. No such wish is recorded as existing in any organised way before the campaign; department stores of the period were, by most accounts, more often asked for depilatory powder to deal with hair on the arms and face than under them.

Ms Anand, who lives in a rented flat on Nicholson Street, said she worked this out while half-watching a documentary on the history of advertising and simultaneously shaving in the shower, a coincidence she described as "genuinely upsetting." She calculated, on the spot, that she has spent what she estimates at eleven full days of her life, in total minutes, removing hair that a company began persuading women to be embarrassed about a hundred and eleven years ago, for reasons that had nothing to do with hygiene and everything to do with selling a razor that, until then, had no market among women at all.

"I actually stopped shaving for about three weeks after I worked that out," Ms Anand said. "It felt amazing. Properly amazing."

She has since resumed, but by a different method: a course of laser hair removal at a clinic on Victoria Street she signed up for in September, on a payment plan, after deciding that permanent removal would at least mean she never had to think about the original marketing campaign, or make the decision, ever again.

"It's not the same as the razor thing," she said. "This one I'm doing for me." Asked what prompted her specifically to do it in September rather than at any other point in the previous fifteen years, she said she had seen an advertisement for the clinic on her phone "a lot," and could not immediately recall where.