The Culture Secretary has challenged social media giants including Twitter and Facebook to do more to keep children safe online.
During a meeting on internet safety, Karen Bradley told technology firms including Twitter, Facebook, Snapchat and Google that they must work together more closely and with the Government to tackle the risks young people face when using the internet.
The companies were summoned to Whitehall for the summit as part of the Government's work on its Internet Safety Strategy, which focuses responding to issues such as sexting and cyber bullying.
"Creating a safe online environment for our children is a major challenge that we face as a society today, and one we must all face up to together," Ms Bradley said.
"Social media companies have a responsibility to protect people who use their technology, and we want to hear what more can be done to keep children and young people safe from online threats.
"This Government is determined to make Britain the safest country in the world for young people to be online, and to make sure that everyone - including the public sector, technology firms, parents and children themselves - is playing their part."
The social media giants were criticised by MPs last month over the handling of illegal and extreme content on their sites, while Facebook and Google have also been warned they must do more to curb the spread of fake news stories on their platforms.
Facebook has since launched a new tool claiming to help users identify fake news stories, but fresh reports of false articles linked to Lord Sugar and Professor Stephen Hawking appearing on the site emerged over the weekend.
The social network said it works "constantly to reduce any type of misinformation".
Baroness Joanna Shields, the Government's internet safety and security minister, said internet companies needed to place user safety closer to the centre of their work.
"The internet can enrich children and young people's lives by giving them new ways to communicate, learn and express their creativity," she said.
"But it is also important to recognise the challenges this new technology presents. Our children are vulnerable to a range of risks - from being exposed to material they may find upsetting to falling victim to cyber bullying or online harassment.
"This Government is working with industry through initiatives like the UK Council for Child Internet Safety and the Internet Safety Strategy to encourage technology companies to follow the important principle of safety by design."