As it follows, the URL pointing to that specific Wikipedia page has been blocked in the UK. The blocked page is an article about the "Virgin Killer" album, recorded by German rock band The Scorpions back in 1976.
The original album image (which caused the controversy) depicts a naked prepubescent girl. The image was designed by Steffan Böhle (the product manager for RCA Records) and the photograph was taken by Michael von Gimbut.
The image caused a bit of controversy at that time as well and the image cover had to be changed eventually.