A 21-year-old man was arrested on Sunday after a feminist campaigner was repeatedly sent abusive messages - including rape threats - on Twitter.
Scotland Yard said in a statement to The Register that the suspect was cuffed in Manchester over claims of harassment. The Met added:
The arrest is in connection with an allegation of malicious communications received by officers in Camden on Thursday, 25 July.
Caroline Criado-Perez, who successfully campaigned for the face of novelist Jane Austen to appear on England's banknotes, made a formal statement to police on Sunday about being aggressively trolled online.
She went to the cops after being repeatedly sent threats of rape. The abuse first appeared on the day the Bank of England confirmed that Austen would be printed on £10 notes, she added.
Describing the trolls, Criado-Perez said she had "stumbled into a nest of men who co-ordinate attacks on women". At one point, the campaigner said she received 50 such messages an hour on Twitter over the space of a 12-hour period.
In June, the Director of Public Prosecutions Keir Starmer published definitive guidelines on tackling the growing web trolling phenomenon, in which he called for a measured approach from police to prevent the courts from being clogged up with complaints.
According to his recommendations for prosecution lawyers, a communication must be "more than offensive, shocking or disturbing, even if distasteful or painful to those subjected to it" before it can be considered unlawful. But he did acknowledge the right to freedom of expression in his memo.
Starmer added that prosecutors needed to weigh that against "communications that should be robustly prosecuted, such as those that amount to a credible threat of violence, a targeted campaign of harassment against an individual or which breach court orders".
The guidelines were drawn up in the wake of an explosion in online trolling cases reported to cops, which led the director to warn that the courts could end up overrun with allegations - because the internet is host to countless horrible messages a day.
Twitter encourages harassed tweeters to submit reports to the micro-blogging site. The company will then look at individual cases to determine whether its usage rules have been breached.
The company said:
We don't comment on individual accounts. However, we have rules which people agree to abide by when they sign up to Twitter. We will suspend accounts that once reported to us, are found to be in breach of our rules. We encourage users to report an account for violation of the Twitter rules by using one of our report forms.
However, at present, only the Twitter iPhone app allows individual tweets to be flagged up as abusive. The social network said it was planning to bring that feature to other platforms including Android and its web interface. ®