That's if they fail to remove harmful or abusive content
That would be the maximum fine under new legislation being prepared by arts and media minister Catherine Martin.
She's told the Sunday Times the material could relate to the likes of child sex abuse, terrorism, cyber-bullying and eating disorders.
A new Media Commission will be set up that can hand out fines to social media sites, search engines or messaging apps that don't comply with repeated requests to take down content.
