The Internet Watch Foundation (IWF) has openly admitted adding a URL from the Wikipedia domain to their blacklist [http://www.iwf.org.uk/media/news.249.htm]. From the IWF news release:
"The specific URL (individual webpage) was then added to the list provided to ISPs and other companies in the online sector to protect their customers from inadvertent exposure to a potentially illegal indecent image of a child."
Sounds like censorship to me, especially since the linked Wikimedia bug report lists instances of fake 404 pages being served in response to requests for http://en.wikipedia.org/wiki/Virgin_Killer.
"The specific URL (individual webpage) was then added to the list provided to ISPs and other companies in the online sector to protect their customers from inadvertent exposure to a potentially illegal indecent image of a child."
Sounds like censorship to me, especially since the linked Wikimedia bug report lists instances of fake 404 pages being served in response to requests for http://en.wikipedia.org/wiki/Virgin_Killer.