Trying to police the Internet is such a ridiculous task to waste your time with, and one which is really beginning to frustrate me. Digital Economy Act wants ISPs to take responsibility for users' filesharing and disconnect them accordingly; gives power to block websites for an array of ridiculous reasons; and if it's pushed ahead, it's going to cripple small ISPs and force up prices all round.
Similarly, trying to block porn is both very expensive and impractical. Think how many porn websites there are; how quickly they're made; how it's shared elsewhere e.g. peer-to-peer sharing; how many users will view it - monitoring alone would be a near-impossible task for GCHQ, let alone ISPs.
And let's be honest, there are always ways around. You can access The Pirate Bay through proxies for example; one of the most basic forms of bypassing. People will always find a way.
Then we come on to the morals. Now, I do feel it does a lot of damage in relationships, health, and psychologically; it's also objectifying and sometimes just distasteful; but a ban isn't the answer. Education and a culture shift is needed if it's something the government wants to change - either a realisation that most porn isn't realistic, and the health issues associated with over-exposure to it. Each to their own though - if consenting adults enjoy making or watching it, that's cool.
In terms of age, I think we need to realise that age of [sexual] consent is a non-working form of generalisation. What is it about being 16 that makes me suddenly able to consent? Why can we have sex at 16, but can't watch people having sex until we're 18? It doesn't deal with people as individuals.
Finally, at the end of the day, if someone wants porn, they'll find a way - TV, DVDs (do porn Blu-Rays exist?), magazines, or whatever.