A row has broken out over plans to put the Government’s landmark internet safety laws on hold until a new prime minister is in place.

The Online Safety Bill had been making its way through Parliament but is now understood to have been delayed until the autumn.

The Bill had been regarded as a major landmark in the regulation of the tech sector, with social media and other platforms set to be held accountable for finding and removing harmful content from their sites, with a particular focus on protecting children.

The delay could be detrimental in the fight to keep children safe online, some campaigners warned, though others welcomed it as a chance to rethink the legislation.

Andy Burrows, head of child safety online policy at the NSPCC, said: “The Online Safety Bill is a crucial piece of legislation that is fundamentally about protecting children from harm and abuse that is taking place on an industrial scale on social media.

“Any delay will mean families continue to pay the price for the failure and inaction of tech firms, who have allowed harm to fester rather than get their house in order.

“Online regulation is therefore vital to force their hand, and delivering this legislation should be a cornerstone of any Government’s duty to keep the most vulnerable in our society safe.”

Free speech campaigners said the Bill is too far-reaching and could lead to censorship when it asks platforms to take down content designated “legal but harmful”.

Former MP Ruth Smeeth, now chief executive of the free speech campaign group Index On Censorship, said the delay is “great news” and claimed the Bill is “fundamentally broken”.

“It was absolutely wrong to try and push through a Bill that takes away the British public’s free speech rights while Parliament was distracted,” she said.

“This is a fundamentally broken Bill. The next prime minister needs a total rethink.

“It would be catastrophic for ordinary people’s free speech, it would give tech execs like Nick Clegg and Mark Zuckerberg massive amounts of control over what we all can say online, it would make the UK the first democracy in the world to break encrypted messaging apps, and it would make people, like myself, who have experienced abuse online, less safe by forcing platforms to delete vital evidence.”

The row has also reached the Conservative leadership contest, with candidate Kemi Badenoch saying the Online Safety Bill in its current form should not become law and calling the delay the “right move”, adding that if she is elected as leader of the Tories she will “ensure the Bill doesn’t overreach”.

Culture Secretary Nadine Dorries, who is spearheading the Bill and backing Foreign Secretary Liz Truss to be the next leader of the Tories, replied: “Which part of the Bill legislates for hurt feelings, Kemi?”

Tech minister Damian Collins – who is backing Penny Mordaunt as the next Tory leader – said Ms Badenoch is “completely wrong” on the issue.

“Tell me where in this Bill there is any provision that requires the removal of legal speech. Instead, for the first time, we can set safety standards online based on our laws. Why would you want to stop that?” he asked.

The legislation was provisionally due to go before Parliament next week but the PA news agency understands it has been delayed to allow for a confidence vote in the Government and the next stage of the Northern Ireland Protocol Bill to take place ahead of recess.

However, sources said the Bill is expected to be tabled in the autumn, once the new prime minister has taken office.

Labour MP and shadow culture secretary, Alex Davies-Jones, said the decision is a “devastating blow” and accused the Tories of “prioritising their own ideals over people’s safety online”.

Ofcom is set to take on the regulator’s role.