The HM Courts & Tribunals Service has apologised for "mistakenly" publishing the names of defendants, which identified the victims of sexual crime, on its court listing website.
Any details that can lead to the identification of victims of sexual crimes are not allowed to be made public, under UK law.
The names published were those of the two mothers who have been accused of letting Lostprophets frontman Ian Watkins abuse their babies.
HM Courts & Tribunals Service told the BBC: "We apologise that the names in this case were mistakenly included on our court listing site.
"The names were quickly removed from the site and action has been taken to ensure this does not happen again."
Peaches Geldof has recently apologised for tweeting the names of the defendants, and has deleted the messages from Twitter.
The UK's attorney general has today published advice on Gov.uk and Twitter to help prevent social media users from committing a contempt of court.
Attorney general Dominic Grieve said: "In days gone by, it was only the mainstream media that had the opportunity to bring information relating to a court case to such a large group of people that it could put a court case at risk. That is no longer the case.
"This is not about telling people what they can or cannot talk about on social media. It's designed to help facilitate commentary in a lawful way. I hope that by making this information available to the public, we can help stop people from inadvertently breaking the law, and make sure that cases are tried on the evidence, not what people have found online."
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