The U.K.-based Internet Watch Foundation (IWF) today reversed a decision made earlier this week which effectively cut off the majority of British Internet users to the popular online encyclopedia Wikipedia.

The IWF bills itself as: “The UK Hotline for reporting illegal content specifically: Child sexual abuse content hosted worldwide and criminally obscene and incitement to racial hatred content hosted in the UK.”

As such, it issued a blacklist warning for a single page at Wikipedia, reported to it by a reader. The page in question contained a photo of a 1970s vintage album cover which featured an image that the IWF said qualified, under its rules, as child pornography.

The problem was not that one Wikipeda page was subsequently blocked by UK Internet Service Providers (ISPs). Rather, it was the way they blocked it, which resulted in more than 90 per cent of UK Internet users being unable to reach Wikipedia at all, much less view any encyclopedia entries.

The IWF, however, reversed the original decision following an appeal by the Wikimedia Foundation, which runs Wikipedia:

“The IWF board has today considered these findings and the contextual issues involved in this specific case, and — in the light of the length of time the image has existed and its wide availability — the decision has been taken to remove this Web page from our [black]list.”

…And then apologised to Wikipedia users:

“IWF’s overriding objective is to minimise the availability of indecent images of children on the internet, however, on this occasion our efforts have had the opposite effect. We regret the unintended consequences for Wikipedia and its users.”

The IWF also noted that it will not blacklist other Web sites which post the offending image — provided they are hosted outside the UK.