Who are "they"? British authorities does not block anything directly.
A few sites are covered by DNS/IP blocks by network providers separate to the Online Safety Act, but no sites are - at least so far - blocked by providers because of the OSA. These are mainly piracy related. E.g. The Pirate Bay.
The blocks/age verification due to OSA are done by the sites themselves under threat of steep fines.
This is all in the finest British tradition of passing the responsibility to someone else so you can point fingers when you get blamed. UK authorities love getting industry to "self regulate" as much possible, under threat of more restrictive laws or court challenges when they don't regulate hard enough.
The upside from a government point of view is that these blocks then are hard to challenge in court.
A few sites are covered by DNS/IP blocks by network providers separate to the Online Safety Act, but no sites are - at least so far - blocked by providers because of the OSA. These are mainly piracy related. E.g. The Pirate Bay.
The blocks/age verification due to OSA are done by the sites themselves under threat of steep fines.
This is all in the finest British tradition of passing the responsibility to someone else so you can point fingers when you get blamed. UK authorities love getting industry to "self regulate" as much possible, under threat of more restrictive laws or court challenges when they don't regulate hard enough.
The upside from a government point of view is that these blocks then are hard to challenge in court.