Twitter boss apologises after threats to female journalists

Twitter's UK boss has personally apologised to women who have been attacked by "trolls" on the social networking site.

Tony Wang, general manager of Twitter UK, has vowed to do more to protect people from abuse.

It comes after growing concerns over abuse on the site - three female journalists said they had been the subject of bomb threats, while two received threats of rape.

Grace Dent, a journalist from Carlisle, who writes for the Independent, is one of several women to receive the threats.

Twitter says it 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.