The journalist Johann Hari has admitted being behind a string of fake Wikipedia entries, including one where another commentator was described as "antisemitic".
Mr Hari became the subject of a media storm in June after it emerged that an interview with Haaretz writer Gideon Levy included Mr Levy's exact comments in a piece he had written at an earlier date.
It then transpired that this was not the only instance of such behaviour.
Mr Hari, the recipient of the prestigious Orwell Prize for journalism in 2008, was suspended amidst accusations of plagiarism.
In a mea culpa posted on the Independent website, he expressed regret about his actions and said he was behind the creation of the internet user "David Rose".
He wrote: "The other thing I did wrong was that several years ago I started to notice some things I didn't like in the Wikipedia entry about me, so I took them out."
Mr Hari went on to explain that he also edited other people's profiles to correct information, but added: "In a few instances, I edited the entries of people I had clashed with in ways that were juvenile or malicious.
"I called one of them antisemitic and homophobic, and the other a drunk. I am mortified to have done this, because it breaches the most basic ethical rule: don't do to others what you don't want them to do to you. I apologise to the latter group unreservedly and totally."
According to Observer journalist Nick Cohen in a Spectator post earlier this year, one of his victims was the then New Statesman deputy editor Cristina Odone.
"Her husband, Edward Lucas, went online to defend her reputation, but 'David r from Meth Productions' tried to stop him," wrote Mr Cohen.
Mr Hari said he planned to take an unpaid leave of absence from the Independent and would return in 2012, after he had completed journalism training. He also said he was returning the Orwell Prize.