As Gina Martin launches her new book, a toolkit for new-gen campaigners, she talks to Fleur Britten about changing the world — and yourself — for the better.

When Gina Martin was 16, all she cared about was, she says, "wanting to make out with Kevin — but Kevin didn't fancy me". Martin may have succeeded recently in making upskirting — the act of taking photos up someone's skirt without consent — a crime in England and Wales, but, she insists, the only difference between her, a "regular working-class person" with "very mediocre" academic grades, no political or legal experience