Isabella Sorley, 23, used Twitter to tell campaigner Caroline Criado-Perez to “go kill yourself” and “rape is the last of your worries” among other abuse.
During the hearing, Westminster magistrates were yesterday read the threatening messages John Nimmo, 25, had posted about Ms Criado-Perez.
Sentencing Sorley to 12 weeks in prison and Nimmo to eight weeks, Judge Howard Riddle said it was “hard to imagine more extreme threats”.
The pair bombarded Ms Criado-Perez with the abusive messages last year after she led a successful campaign using social media for a female figure to appear on a Bank of England note.
Judge Riddle said that, despite the defendants’ claims, the harm threatened against Ms Criado-Perez “must have been intended to be very high”.