The internet can be a terrible place. Even on the most respectable of mainstream news sites the web seems to bring out the worst in many people: open comment threads and social media are often poisoned by racism and sexism one seldom hears offline. Women, in particular, routinely face barrages of abuse – often threats of murder and rape. And, sometimes, these do not come from one or two strangers, but a swarm.

This week, British feminist campaigner Caroline Criado-Perez became the highest-profile target to date. Her offence was to convince the Bank of England to put the image of a woman – Jane Austen – on the ￡10 note. In response, she has been harassed relentlessly by scores of people via email and Twitter, the social networking platform, with threats of rape, obscene sexualised insults and attempts to establish and publish her address.

When prominent women expressed support for her, they too were targeted. MPs Stella Creasy and Claire Perry have, in turn, been threatened: one individual spoke of cutting off Ms Creasy’s breasts.