Tech giants must not be allowed to use online age checks to harvest children’s facial and biometric data, a leading peer has warned.

Baroness Kidron, the architect of the UK’s first statutory online children’s protection code, said the new online harms regime needs to mandate that tech companies delete any personal and biological data they use to verify users’ ages.

The warning comes as the Government’s incoming Duty of Care laws, which The Telegraph has campaigned for since 2018, meaning Silicon Valley giants will face fines potentially running into the billions if they fail to keep children off their sites and apps.

However, ministers are considering letting companies use “age assurance” techniques alongside traditional checks like users submitting copies of their passport or driving licence.  

Age assurance instead attempts to work out a person’s age using a range of “signals” that can include facial and voice recognition.

Baroness Kidron has introduced a private members bill, which is having its second reading today/Friday, proposing mandatory ‘minimum standards’ for age assurance technology, including that any sensitive data collected is not then used for commercial purposes.

Speaking to The Telegraph, the peer said: “This is a developing technology and those people who do voice and face recognition are saying we are within months of being able to say how old someone is. 

“But the question is what are they doing with that information? My bill says you can use voice or a snippet of my voice, but what are you then going to do with that snippet, who will you share it with and how quickly will you discard it?”

The private member’s bill has been backed by the Children’s Commissioner Rachel de Souza as well as the NSPCC and Ian Russell, the father of the schoolgirl Molly Russell, who took her life after viewing self-harm material on social media sites.

There are already serious concerns among rights’ groups over children’s biometric data being collected by tech companies.

A High Court case was launched by a 12-year-old girl last year against the Chinese-founded social media site TikTok, which accused the company of harvesting children’s facial recognition data without their consent.

Meanwhile, Baroness Kidron, who is a film director and documentary maker, said minimum standards are also needed to ensure that ‘age assurance’ actually works in keeping underage children off social media and tech sites where they can be exposed to harmful content.

Recent Ofcom research found that almost half of five to 15-year-olds are using TikTok and a third Facebook, Instagram and Snapchat, even though the apps have a minimum age of 13.

Baroness Kidron added: “Children, young people and parents are telling us loud and clear: they are struggling, are made to feel vulnerable and anxious and their wellbeing is undermined by digital services and products. We must act now to protect them from these online harms.”

The peer, who is the chair of the children’s charity 5Rights, has been a leading campaigner in recent years to make the internet safer for children.

A 2018 amendment she made to data protection laws created the Age Appropriate Design Code, which means tech companies can now be fined billions if they misuse children’s personal information.