Wikipedia, the controversial online encyclopaedia, is planning to ask its army of faceless internet editors — known as Wikipedians — to verify their credentials after one of the most prolific of their number was exposed as a fraud.

The online reference work was dealt a serious blow last week as it emerged that EssJay, a Wikipedia editor understood by the site and its users to be a tenured professor of religion at a private university with expertise in canon law, was in fact a 24 year old from Kentucky called Ryan Jordan with no higher educational qualifications to speak of.

What is more, Mr Jordan’s expertise and dedication to the site seemed so great that he was given a full time job at another company run by Jimmy Wales, the Wikipedia founder.

After initially ignoring the problem, Mr Wales has since asked Mr Jordan to resign from Wikia, the internet company he controls, and has removed him from the Wikipedia website.

Wikipedia has come under fire from all sides amid claims that much of its content is unreliable and prone to internet vandals who deliberately print false information on the website.

The EssJay affair, which has enraged critics and supporters of Wikipedia in equal measure, is the most serious instance of fraud experienced by the website so far.

The Wikipedia founder was in Japan when the EssJay fraud was exposed in the US.

Mr Wales said the site and its users will soon devise a scheme to adequately check credentials of those Wikipedia editors who claim to possess them. But Wikipedia, by its nature, is self-policing and its experts are not required to have credentials, so a valid check will be hard to implement.

"I don't think this incident exposes any inherent weakness in Wikipedia, but it does expose a weakness that we will be working to address," Mr Wales said. "The only thing inherent in the Wikipedia model is a volunteer effort to create the highest possible quality encyclopedia. Mr Wales told The Times that he is "personally saddened" by the identity fraud in one of his most trusted editors, and confessed that he did not take the issue as seriously as he should have done.

Mr Wales first thought Mr Jordan was merely using a false identity to protect himself from online cranks and maintains that his 20,000 or more entries in the Wikipedia have never been called into question.

"He got himself into this years ago, and kept it up because he saw no way out," the Wikipedia founder said. "He started his deception before we became friends, and I was not particularly aware of his alleged credentials. I know him as an excellent editor." Mr Wales admitted that Wikipedia users and editors alike operate using a much higher degree of trust than many in the real world find unusual, but that the Wiki model had weeded out a falsehood in the end.

"Mr Ryan was a friend, and still is a friend," the Wikipedia founder said. "He is a young man, and he has offered me a heartfelt personal apology, which I have accepted. I hope the world will let him go in peace to build an honourable life and reputation."

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