> it is possible to verify your age without disclosing who you are to the site you're visiting, and without disclosing what site you visited to the government.
I can't believe people are really okay with a system where you have to show your real face to access websites. Cameras on phones went from a novelty to a government mandate so you can be observed.
There are various other potential methods to verify one's age, all of which are forbidden by OFCOM. Account age, zero-knowledge proofs, key signing, some kind of OAuth thing, physical tokens that require proof of age to buy, etc. The only permitted ones require your to link your real-life identity. This is a huge boon to the intelligence services and law enforcement.
Even among the few permitted verification methods, there are obstacles. Each site usually provides only one verification method at one verification provider. You may have to trust a company you never heard of before. Sometimes the photo fails (maybe their system thinks you don't look old enough) and they ask for ID too, or the photo fails and you are locked out of verification. Some services only allow credit card verification (e.g. Steam), so if you have poor credit you aren't able to even view the store page despite being of age.
What I say is, we don't need any of this. For thirty or so years we had client-side optional Parental Controls, and it worked fine. Many adult sites voluntarily use a tag to ensure sites are correctly identified. The ability of adults to access adult content was not impeded. Parental Controls work better than verification because 1) many sites will not deploy age verification, and 2) it's trivial to overcome photo-based ID by holding your device up to a picture of an adult on a television set.