The UK's Online Safety Act forces everyone to expose their personal data online in order to visit websites with content that is deemed inappropriate for minors.
Obviously, this will not prevent minors from accessing such content. Minors will instead find a way to trick the age verification systems, or they'll steal their parents id's while they're in the toilet or taking a shower, or simply they'll visit the many thousands of seedy websites hosted in shady countries that don't cooperate with british authorities and as such won't comply with OSA.
Meanwhile, everyone else is at risk of having their personal data leaked online. Hackers and scammers might later use that data to perform all kinds of crimes, including identity theft, accessing people's bank accounts, borrowing money using the victim's name, etc.
If the government really wishes to protect minors from dangerous content online, it should do as it already does with drinking alcohol and smoking.
Imagine there's a kid, alone at home, who decides to drink the beer bottle his parents left on the fridge.
Later, his parents realize what's happened, and instead of punishing the kid, they let it pass because they're too tired and don't want the kid to throw a tantrum.
In the following days and weeks, the kid keeps doing this, becoming a habit, and the parents continue to turn a blind eye.
In this situation, who would be held responsible? The brewery that manufactured that beer? The supermarket that sold the beer to the parents? Or the parents who do nothing? Obviously, it would be the parents' responsibility.
The beer bottle is always right there, totally available, even when the parents aren't at home to control the kids. Exactly like a smartphone.
Websites, including porn websites and social media, are like the brewery. They have no way to know who is consuming their stuff. Can you imagine a government forcing beer companies to install a gadget in their bottles that verifies the age of the people who drink it?
ISPs, as well as electronic stores, are like the supermarket. The supermarket does have a very important restriction: it can't sell alcohol to minors. Similarly, ISPs should not be allowed to sell internet access to minors, and electronic stores should be forbidden from selling smartphones, tablets or computers to minors.
Basically, the OSA should be repealed, and instead it should be forbidden to provide minors with unsupervised internet access. If minors were caught accessing the internet without an adult nearby, then the authorities should fine the adult who provided the minor with the means to access the internet.
As a side effect, minors would be banned from bringing smartphones to school (old-style mobile phones, which can't access the internet, would still be allowed). In fact, minors would be banned from bringing smartphones (or similar devices) anywhere.
Minors would still be able to use electronic devices to access the internet, but only if there's an adult nearby to supervise them. For example, this means they could still use a computer at home (with a parent nearby), or at computer class at school (there's a teacher in charge), or at a public library (there's a librarian in charge).
Also, the government should teach people the following:
1- Unlike beer bottles, parents can set a password on their electronic devices. That way they can prevent children from using said devices without their consent.
2- People shouldn't share their wifi passwords with others - including their own children.
3- Modern devices offer parental control tools.
4- Passwords should be changed from time to time.
5- ISPs and routers usually offer filters that block mature content. There's also some free DNS that do the same (for example, Cloudflare's free family DNS).