The measures are set out in the Online Harms White Paper, a joint proposal from the Department for Digital, Culture, Media and Sport (DCMS) and the Home Office which has been published today.

It includes a mandatory duty of care which will require companies to take reasonable steps to keep their users safe and tackle illegal and harmful activity on their services.

The regulator - which could either be a new or an existing body - will have effective enforcement tools, and the government has launched a 12-week consultation on powers to issue substantial fines, block access to sites and potentially to impose liability on individual members of senior management.

The new proposed laws will apply to any company that allows users to share or discover user-generated content or interact with each other online, including social media platforms, file hosting sites, public discussion forums, messaging services, and search engines.

Prime Minister Theresa May said: “The internet can be brilliant at connecting people across the world - but for too long these companies have not done enough to protect users, especially children and young people, from harmful content.

“That is not good enough, and it is time to do things differently. We have listened to campaigners and parents, and are putting a legal duty of care on internet companies to keep people safe.

“Online companies must start taking responsibility for their platforms, and help restore public trust in this technology.”