The Government has been urged to reconsider plans to hold back criminal sanctions for senior managers at social media firms for breaking proposed internet safety laws.

The Online Safety Bill, published earlier this week, aims to give Ofcom the power to fine companies and block access to sites, but the power to make senior staff liable for rule breaches is being deferred for at least two years.

Children’s charity the NSPCC said this fails to properly hold social media platforms to account and misses the opportunity to better protect children from abuse online, and urged ministers to reconsider.

Giving evidence to the House of Commons Digital, Culture, Media and Sport (DCMS) Committee, Culture Secretary Oliver Dowden said the sanction had been deferred because he believed potential fines would be more damaging to platforms that breached the proposed rules.

This is a unique chance to move beyond the status quo that sees action taken only after serious harm has occurred, but deferring liability for senior managers misses the opportunity to finally put children first

“I think most (social media) companies are much more motivated by financial consequences than they are by the criminal liability of individual people,” he told MPs.

He added that “if the laws weren’t working properly” when the new rules were reviewed after two years, the Government would seek to enact the criminal liability power.

Under the proposals, companies that breach the new duty of care to users could be fined up to 10% of annual global turnover, which could amount to billions of pounds in the case of larger platforms such as Facebook.

But Andy Burrows, head of child safety online at the NSPCC, said this was not enough.

“If the threshold for enacting criminal sanctions is regulation failing, the reality will be further years of children facing grooming and abuse that could have been avoided,” he said.

“This is a unique chance to move beyond the status quo that sees action taken only after serious harm has occurred, but deferring liability for senior managers misses the opportunity to finally put children first.

“The Culture Secretary should learn from other regulated sectors that hold named managers responsible for the safety of their products, with the threat of fines, censure and, as a last resort, criminal sanctions leading to a culture of compliance.”

The criticism came as other campaigners raised concerns about the Bill’s impact on privacy and freedom of expression.

Civil liberties group Big Brother Watch said the proposed requirement for larger platforms to clamp down on content that the Bill describes as “legal but harmful” was “too vague” and amounted to “state-backed censorship”.