By Anthony Bond PUBLISHED: 07:16 EST, 3 August 2013 | UPDATED: 10:11 EST, 3 August 2013 Moving forward: The UK boss of Twitter, Tony Wang, pictured, has personally apologised to women who have been attacked by 'trolls' on the social networking site The UK boss of Twitter has personally apologised to women who have been attacked by trolls on the social networking site and vowed to do more to protect people from abuse. Tony Wang, general manager of Twitter UK, posted a series of tweets today saying abuse was 'simply not acceptable.' There has been growing concern over abuse on the site after three female journalists said they had been the subject of bomb threats, while two received threats of rape.
@highlight
Tony Wang posted series of tweets today saying abuse was 'not acceptable'
@highlight
Twitter today clarified its rules on abusive behaviour
@highlight
It follows growing backlash over a series of attacks on women
@highlight
Scotland Yard investigating allegations by eight people of abuse on Twitter
An online petition calling for @placeholder to add a 'report abuse' button to tweets has already attracted more than 124,000 signatures.