No it's not because U.K. ISPs have revealed that the filter will censor other content, as well.
"As well as pornography, users may automatically be opted in to blocks on "violent material", "extremist related content", "anorexia and eating disorder websites" and "suicide related websites", "alcohol" and "smoking". But the list doesn't stop there. It even extends to blocking "web forums" and "esoteric material", whatever that is. "Web blocking circumvention tools" is also included, of course." [1]
[1] http://www.wired.co.uk/news/archive/2013-07/27/pornwall
The bottom line is that if you don't want your children to be exposed to content that may be questionable, don't let them get on the Internet. Set a password on your computer. Install a filtering program which don't require any technical expertise to install whatsoever. Hell, Windows has a web filter build in now a days. Don't force your preposterous views on to me. The government has no place restricting legal content. I'm tired of these bullshit "Think of the children!" arguments.