As there are a multitude of broadband providers, if this is a feature that was high on the wish-list of customers, we would see it advertised in huge print from the likes of BT/Talktalk etc. It's called having a free market, and market forces.
However we don't. In fact they seem to hide restrictions (caps on unlimited connections for example), which can only indicate one thing. People don't want it! What people want is a reliable high-speed connection, and HMgov have managed to do nothing about that! How about "All houses to have at least 20Mbs by 2011" for a sound bite? That would get more attention.
Filtering smut is impossible. It would be easier if the .xxx TLD was approved but politicians don't seem to get that and object to it. Even so it will be still scattered anywhere and everywhere. Politicians love the sound bites, but know nothing about how the internet works. Neither do their advisors, or the advisors of the advisors. Jen from IT crowd springs to mind, an army of them in ill-fitting shoes! Even if they did manage to block some of it, every 12 year old boy would quickly locate it somewhere else that the men in suites and women in tight shoes had never considered (or knew existed), such as usenet, remember that? Oh yes, that's still alive, and yes, full of smut!
HMGov should keep their noses out of people's business, and out of the money trough too whilst they're at it.
If they want to do something useful, they should direct some of their hot air at the UK airports to defrost the planes, I'm getting a bit bored of the continually rotating snow news!