Despite privacy concerns, the government maintains that updated internet safety laws will improve child protection online.
Services that publish or permit pornographic content will have to verify their users' ages under the Online Safety Bill.
Digital rights organizations, however, claim that the tools and the methods used to collect people's data are not transparent.
Paul Scully, the minister of technology, acknowledged that "no piece of legislation is ever going to be perfect," but that it was "flexible.".
According to the proposed amendments, user-to-user platforms that permit pornographic content will be required to employ age-checking tools that are "highly effective" at determining whether a user is a child or not, such as those that can determine a user's age from a selfie.
Other techniques include verifying official identification, checking bank statements, or using voice recognition software to determine whether the person attempting to access their service, who is anonymized, is older than 18.
The protection of people's privacy hasn't won over digital rights activists.
According to Dr. Monica Horten, policy manager for freedom of expression at Open Rights Group, age assurance technology is being "introduced in quite a draconian way.". She argued that the dangers of requiring websites to confirm users' ages needed to be taken into account more.
The age of people can be determined by some of these systems using facial recognition technology. All parents should be extremely concerned about private companies amassing sizable databases of children's biometric data without any governance frameworks in place.
"We don't understand how these systems operate. She asked, "Is our data being stored, who has access to it, and if so, are they processing it?
With the passage of the bill, the communications watchdog Ofcom will have the authority to fine tech companies, censor websites, and impose criminal penalties on company executives who don't cooperate.
The requirements of the bill are welcome, according to Iain Corby of the Age Verification Providers Association, but "before the bill is finalized, the government still needs to give the regulator better powers to enforce at scale with five million adult websites," he said.
The possibility of discrimination against certain socioeconomic groups, who are more likely to lack these documents, has also been brought up by the requirement that users provide official documentation.
Mr. Scully dismissed criticism that the legislation might result in the blocking of essential sexual health education material.
In those fields, he said, "I want to reassure people that they won't be harmed by this bill.".
According to Mr. Scully, Ofcom would set the rules for deciding "what is and isn't available for under-18s.".
According to research, children are exposed to online pornography as young as nine. By the time they were 13 years old, about 50% had experienced it.
To circumvent age restrictions on websites, some teenagers simply lie about their birthdate.
The changes, according to Mr. Scully, "stop the majority of children - who don't look for VPN or don't look for other ways around this - to be able to almost trip over access to pornography, as is the case at the moment.".
The UK has struggled with how to safeguard social media users—and in particular children—from harmful content without compromising free speech.
After deciding to toughen the law in January with the threat of jail time for tech executives, new measures will also seek to hold top executives personally accountable for maintaining children's safety on their platforms, the government announced.
Other amendments to the legislation will enable authorities to learn about a child's social media use at the coroner's request, which will assist the families of the deceased in understanding any potential role played by online activity in their demise.
Sections of the Online Safety Bill have drawn criticism from the tech sector, including companies like Apple, in particular clauses that could be used to force messaging services to break end-to-end encryption in order to search for child abuse content.
Before the bill is put to a vote, the government declared that no additional amendments would be made to that section.
Next week, the House of Lords will vote on the bill, which might not be passed for several months.
