Labour MP Stella Creasy has called in police after she was subject to a torrent of rape threats on Twitter following her decision to stand up in support of a feminist campaigner who suffered similar abuse.
Caroline Criado-Perez was inundated with abusive and threatening messages, many mentioning rape, after she successfully petitioned the Bank of England to feature Jane Austen on the new £10 note.
A 21-year-old man was arrested in Manchester on suspicion of harassment following a complaint relating to Criado-Perez.
While criticising Twitter, the MP for Walthamstow in east London used the social media platform to report her complaints to police, warn her abusers that she was logging their threats, and take screen shots of the offensive messages.
Twitter has come under increasing pressure to review its procedures for reporting abuse, following an outcry among users.
Creasy retweeted some of the messages she had received on the site, warning internet "trolls" that she would be coming for them.
One message sent to Creasy under the user name @rapey1 said: "I will rape you tomorrow at 9pm. Shall we meet near your house?"
Another read: "You better watch your back....Im gonna rape your ass at 8pm and put the video all over the internet."
And another said: "If I meet you in an alley you will definitely get f**ked."
Using the hashtag #taketwitterback, Creasy responded saying: "You send me a rape threat you morons I will report you to the police & ensure action taken."
An online petition demanding Twitter step up its safeguards has attracted 60,000 signatures.
The debate was ironically being carried out almost solely on Twitter. Tony Wang, the general manager of Twitter UK, said the company took online abuse seriously.
He also used Twitter to say: "We encourage users to report an account for violation of the Twitter rules by using one of our report forms.
"Also, we're testing ways to simplify reporting, eg within a tweet by using the 'Report Tweet' button in our iPhone app and on mobile web. We will suspend accounts that, once reported to us, are found to be in breach of our rules."
Shadow home secretary Yvette Cooper wrote to Wang criticising Twitter's response to the abuse Criado-Perez suffered.
Cooper wrote: "Despite the scale and seriousness of these threats, the official response from Twitter continues to be extremely weak - simply directing Caroline away from Twitter towards the police, and, belatedly, directing users to abuse reporting forms on Twitter.
"Of course it is right to report such abuse to the police, and it is very important that they investigate and pursue this case.
"But social media platforms also have a responsibility for the platform they give users. And in particular they have a responsibility not to tolerate this kind of abuse, rape threats and potentially criminal behaviour."
Twitter said it had introduced a button to report abuse on its latest iPhone app and was looking at expanding this function.
However, that was unlikely to satisfy the website's more strident critics. They said the ability to report abuse on Twitter is too time-consuming, particularly for users who become victims of mass-trolling.
Criado-Perez was at one point receiving about 50 alleged rape threats an hour, after winning her campaign to stop the Bank of England replacing Elizabeth Fry with Winston Churchill on the £5 note.
The bank agreed to use Austen's image to replace Charles Darwin on the £10 note, after Criado-Perez gained the backing of 35,500 petition signatories. Creasy was also involved in that campaign.
Criado-Perez will also be making a formal complaint to the Press Complaints Commission after a reporter from a London newspaper knocked on her door late on Sunday to ask about her ordeal.
She said Creasy would complain on her behalf to the newspaper editor after the episode left her "terrified and on edge".