Stricter regulation, including large fines, is one option to force technology companies to take the issue of hate speech more seriously, the Mayor of London has said.
"We can't assume that tech companies will find the solutions by themselves," Sadiq Khan told. He said companies have to be "chivvied and cajoled to take action".
The Mayor shared examples of abuse he has personally received. The messages formed part of his keynote speech at the South by Southwest (SXSW) festival in Austin, Texas.
He said the messages could deter people from entering politics or public life.
"If someone like me is receiving these sorts of messages in a public environment," he said. "Imagine how you feel as a young person, if you're somebody who's putting your head above the parapet.
"You're going to think once, twice three times whether you want to do so."
The location of his speech is fitting - it was here where Twitter first gained popularity back in 2007. But in that decade, little has changed in the law.
"We have evolving economies, which means we should have evolving regulations.
"For too long politicians and policy makers have allowed this revolution to take place around us and we've had our heads in the sand."
In his speech he will reference rules put in place in Germany that allows fines of up to 50 million euros if hate speech is not removed in a timely fashion.
"Germany is an example of where the German government said 'Enough. Unless you take down hate messages, unless you take down fake news, we will fine you'.
He added: "I want to work with the tech companies, but you have to be responsible."