Apparently 95% of ISP have agreed already, which means most people are fucked, sure you can always "opt-out" of it, but that's just admittance to your family(wife/parents/children/husband whatever) that you watch porn... not exactly my cup of tea.
A lot of idiocy going on here, a user on reddit summed it up perfectly, but I can't seem to find it anymore, I'll throw it up if I find it. Obviously this won't eliminate people watching it, but for the average user they won't know what to do.
Here's the bbc article http://www.bbc.co.uk/news/uk-23401076
inb4 fuck bitches