Britain will make social media bosses personally liable for harmful content and shut down offending platforms under a government action plan published yesterday -- the first of its kind anywhere.
The long-delayed and eagerly anticipated proposals lay the groundwork for legislation that could be passed in the coming months.
They were drawn up after consultations with social media moguls such as Facebook chief Mark Zuckerberg and have faced little resistance from other platforms that have also been blamed for allowing the spread of hate and abuse.
Some of the proposals have sparked concerns from free speech groups.
"What we're proposing today is that companies that deal with user-generated content should take greater responsibility for keeping those users safe," culture and media minister Jeremy Wright told BBC radio.
"These are world-leading proposals. No one in the world has done this before."
The proposed regulations would see social media companies accept "duty of care" obligations that require them to identify and remove "online harms".
Those that fail would be first issued warnings and then hit progressively with more punitive sanctions.
The government paper suggests that these include "the creation of new liability (civil fines or extended to criminal liability) for individual senior managers".
The most serious would see internet service providers block non-compliant websites and apps.
"This would only be considered as an option of last resort and deploying such an option would be a decision for the independent regulator alone," the plan says.
The regulations would only apply in Britain and should have no immediate impact on users elsewhere in the world.
But they may prompt other governments to take notice and follow suit.