Television classicist Mary Beard has revealed she was sent a bomb threat on Twitter, hours after the social networking site's UK boss personally apologised to women who have been attacked by "trolls".
Ms Beard, a professor of classics at University of Cambridge, said she had contacted police after receiving a message on Saturday night claiming a bomb had been left outside her home.
She wrote on her Twitter page: "Just got 1 of these messages. A bomb has been placed outside your home. It will go off at exactly 10.47pm and destroy everything. Told police."
She later wrote: "OK all, it's 11.00pm and we are still here. So unless the trolling bombers timekeeping is rotten.... all is well. But how stupidly nasty."
Prof Beard, 58, told BBC Radio Five Live: "There's something very strangely and awkwardly insidious about it. It is is scary and it has got to stop. I didn't actually intellectually feel that I was in danger but I thought I was being harassed, and I thought I was being harassed in a particularly unpleasant way."
The controversy has prompted many Twitter users to observe a 24-hour silence on the site, a move championed by writer Caitlin Moran. She signed off at midnight for the so-called Twittersilence, tweeting: "I really am going now. please don't hassle anyone who doesn't want to join in. See you 12am tomorrow. THANK YOU."
Guardian columnist Hadley Freeman, Independent columnist Grace Dent and Europe editor of Time magazine Catherine Mayer, as well as a number of other women, have previously said they had been the subject of bomb threats on the site, while two received threats of rape.
Tony Wang, Twitter UK general manager, posted a series of tweets on Saturday saying abuse was "simply not acceptable". His messages came after the website clarified its rules on abusive behaviour amid a growing backlash over a series of attacks.
Mr Wang wrote: "I personally apologise to the women who have experienced abuse on Twitter and for what they have gone through. The abuse they've received is simply not acceptable. It's not acceptable in the real world, and it's not acceptable on Twitter. There is more we can and will be doing to protect our users against abuse. That is our commitment."
The company has updated its rules to make it clear that abuse will not be tolerated and has put extra staff in place to handle reports of abuse, it said. The move comes as Scotland Yard said its e-crime unit was investigating allegations by eight people of abuse on the microblogging site. An online petition calling for Twitter to add a "report abuse" button to tweets has already attracted more than 124,000 signatures.