The UK will be the safest place in the world to be online, ministers have claimed after flagship legislation finally cleared Parliament.

Technology Secretary Michelle Donelan said the Online Safety Bill was a “game-changing” new law.

The legislation, which has been years in the drafting, imposes new legal duties on big tech companies and service providers, overseen by the regulator Ofcom.

Child safety campaigners welcomed the passage of the Bill, which has had a protracted journey through Parliament and had faced resistance from tech firms concerned about measures which could weaken communication security.

Ms Donelan said the Government had adopted a “common-sense approach” to the legislation.

“The Online Safety Bill is a game-changing piece of legislation,” she said.

“Today, this Government is taking an enormous step forward in our mission to make the UK the safest place in the world to be online.”

Officials said the legislation would tame the “Wild West” of the internet.

The reforms come in response to continuing concern about youngsters accessing pornographic content online, child sexual abuse in cyberspace and the impact of harmful material on social media, which has led young people to take their lives.

Sir Peter Wanless, chief executive of the National Society for the Prevention of Cruelty to Children, said: “At the NSPCC we hear from children about the completely unacceptable levels of abuse and harm they face online every day.

“That’s why we have campaigned strongly for change alongside brave survivors, families, young people and Parliamentarians to ensure the legislation results in a much safer online world for children.”

Barnardo’s chief executive Lynn Perry said: “Every day, children are being exposed to extreme pornography online which harms their mental health and their understanding of healthy relationships, and normalises sexual abuse.

“We are delighted that the Online Safety Bill is heading for Royal Assent. It will make age verification compulsory for pornography sites, social media and other platforms which should stop children from stumbling across and accessing pornographic content. ”

Barnardo’s will “continue to work with the Government to ensure that pornography that would be illegal to buy on a DVD or Blu-ray will be illegal online too”.

The legislation is aimed at making social media platforms responsible for the content they host.

If they do not act to prevent and remove illegal content they will face significant fines of up to £18 million or 10% of global revenue – potentially billions of pounds – and in extreme cases their bosses could even face prison.

TV personality Georgia Harrison, whose ex-partner Stephen Bear was jailed earlier this year for posting intimate footage of her online, has backed the legislation.

She said the new laws would mean “holding social media companies accountable to protect women and girls from online abuse”.

The final stages of the legislation, which was introduced to Parliament in March 2022 when Boris Johnson was prime minister, played out in the House of Lords.

Ofcom’s chairman Lord Grade of Yarmouth was reminded of the responsibilities his organisation would now assume.

Liberal Democrat Lord Clement-Jones said: “It’s over to Lord Grade and his colleagues at Ofcom, in whom we all have a great deal of confidence.”

In response, Lord Grade, who sat on the red benches throughout the Bill’s passage through the upper chamber, pretended to nervously bite his nails.

Independent crossbencher Baroness Finlay of Llandaff said: “I think we all need to wish Lord Grade good luck and all the best as he takes on what is an incredibly important scrutiny role.”

Labour frontbencher Lord Stevenson of Balmacara said: “Isn’t it odd that this historic Parliament, with all our archaic rules and traditions, has the capacity to deal with a Bill which is regulating a technology which most of us have difficulty in comprehending let alone keeping up with.”