[londons_explore]

That is already the case on most ISP's. I don't think it's legally required, but most ISP's do it with a wink wink nod bid agreement with the government.

It helps that ISP's want to do a credit check on their subscribers because then they get paid by credit checking agencies (credit checking agencies love checks for utilities because it gives a strong address to name to payment bounced-or-not linkage, so will either do the check for free, or sometimes even pay the utility for it).

So now the ISP can do a credit check on the subscriber to know their true identity, and know they are over 18, before allowing them to access the checkbox to enable porn sites.