BBC News: Extent of child net porn revealed — BT proactively block sites identified by the Internet Watch Foundation assessed as “illegal to view” under the 1978 Child Protection Act, presumably blocking such sites at the IP level, as they don’t use transparent proxies any more.

However, an interesting comment in the article is:

BT said in its first three weeks its new system, which bars access to particular sites, registered nearly 250,000 attempts to view web pages containing images of child pornography.

[…]

A BT spokesman added: “It could be that one dedicated pervert is making hundreds of attempts to get on websites each day.”

I never thought I’d hear the phrase “one dedicated pervert” anywhere, much less in a BBC News article!