We are entering a new age of accountability for tech to protect children and vulnerable users,” Digital Secretary Oliver Dowden said on Tuesday, as the government revealed the details of its internet regulation plan.

The Online Harms Bill was first proposed by Theresa May’s government in April 2019. The legislation sets out strict guidelines covering the removal of illegal content, such as child sexual abuse, and media that promotes suicide or violence. Websites must obey the new rules or face being blocked in the UK, and the firms’ senior managers could be held liable for content.

Social media platforms such as Facebook and Twitter must abide by a new code of conduct that includes their responsibilities towards children. “We are giving internet users the protection they deserve,” Home Secretary Priti Patel said of the move.

"We will not allow child sexual abuse, terrorist material and other harmful content to fester on online platforms. Tech companies must put public safety first or face the consequences."

The power to fine tech companies up to £18 million ($24 million) – or 10 percent of their global turnover – for breaking the rules will be given to British media regulator Ofcom, which could also be granted the power to block certain platforms from being accessed in the UK.

Online journalism and reader comments on news publishers’ websites will not be covered by the new rules, so as to allow freedom of expression.

Under a new two-tier system for social media, Facebook, TikTok, Instagram and Twitter will be placed in ‘Category 1’ of tech companies with the largest online presences, who will be subject to more responsibilities than firms with a smaller online reach.

Facebook and Google have agreed to work with authorities on the regulations, and China’s video-sharing platform TikTok said it will strengthen online safety.