The founder of the world's leading online encyclopaedia today conceded that "editing your own entry on Wikipedia is generally not a good thing", after it was shown that he had amended his entry 18 times.

In the latest twist of controversy to affect the volunteer-compiled online resource, Jimmy Wales told Times Online that he regretted repeatedly revising the encyclopaedia's entry on himself.

"I would discourage it," Mr Wales admitted. "It raises a lot of questions about whether you can be unbiased about yourself and whether it’s possible to distance yourself from the story.

"I wish I hadn't done it. It's in poor taste."

In common with all of its content, Wikipedia's article on Mr Wales was written by volunteers and can be edited by anyone. Mr Wales's amendments were uncovered by Rogers Cadenhead on his blog.

Mr Wales said that he only made changes to factual errors on the site and noted that he had carried them out under his own name. But his actions will once again call into question the integrity of Wikipedia.

Wikipedia's accuracy was called into question last month when John Seigenthaler, a prominent American journalist, described how an entry had falsely linked him to the assassinations of President John F Kennedy and Senator Robert Kennedy.

Mr Wales responded then by announcing that the site would experiment with "stable" versions of entries that would be reviewed by Wikipedia and then closed to public editing. "Stable" articles would run alongside the current "live" articles, he said.

But Mr Cadenhead has shown how a publicly accessible log of edits to the article on the Wikipedia founder revealed that Mr Wales has changed his own Wikipedia biography 18 times. On seven occasions, he deleted phrases describing Larry Sanger, a former Wikipedia employee, as a co-founder of the site.

From its launch in January 2001, Mr Sanger led the project as "chief organiser", and has been credited with giving the site its name. Today, in an interview with Wired News, Mr Sanger said: "It does seem that Jimmy is attempting to rewrite history.

"But this is a futile process because in our brave new world of transparent activity and maximum communication, the truth will out."

Mr Cadenhead’s blog also described how "another sore spot for Wales has been Bomis Babes, a now-closed subscription service of his company's Bomis.com search portal that offered nude pictures of women".

The site was described by Wikipedia contributors as "softcore pornography" or "erotica".

But Mr Wales changed a reference to "Bomis Babes softcore pornography section" to "Bomis Babes adult content section". He twice altered references to the nature of the site, replacing "Bomis Babes erotica section" with "Bomis Babes blog based on Slashdcode" and other technically-slanted descriptions.

"This was a website – essentially a search engine – with thousands and thousands of pages," Mr Wales said today. "To concentrate on one aspect of it doesn’t really seem to make sense … but that is the kind of thing the media sometimes does.

"The real question here is the ethics of editing your own blog, which I would discourage. But it is very hard to resist."

Last week, on the same day that Wikipedia, was described by Nature, the science journal, as being as reliable as the Encyclopaedia Britannica, the site was targeted by cyber-vandals.

A study by Nature, which found that Wikipedia contained no more "serious errors" than the venerable Encyclopaedia, looked to have repaired some of the damage.

But on Thursday, Times Online found that a search for the term "Wikipedia" revealed the one-line entry: "an encyclopaedia [sic] full of crap".

Later, Wikipedia had posted on its own site this unflattering description: "Although it may seem factual, Wikipedia is largely a web of lies and falsehoods, and it is not to be trusted by any means ... it is worthless".

The changes to Wikipedia's authoring and editing policies are expected to be implemented next month. The site will also create a state of semi-protection for some stories that will delay publication of edits for up to ten minutes. Newly registered users will also be prevented from havingm edit access.

Mr Wales has said that the changes are merely "tweaks" aimed at improving a system he said works well.

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