Lostprophets singer Ian Watkins has been given a 35-year sentence for 13 sex offences, including the attempted rape of a baby.
Watkins, 36, shook uncontrollably as he was handed down the sentence at Cardiff Crown Court, and it was greeted by shouts of "yes" from the public gallery.
Two female co-defendants, aged 21 and 25, were also sentenced for various sex offences, with 'Mother A' given 14 years in jail and 'Mother B' given 17 years. They cannot be named for legal reasons.
Watkins was convicted of sexually touching a groupie's 11-month-old baby, then trying to have sex with the child. He also encouraged a second fan to abuse her child during a webcam chat and secretly stashed child porn videos, some of which he had made himself.
Justice Royce QC told Watkins and the two co-defendants, "what you three did plumbs new depths of depravity".
He said the singer had a "dark and sinister side" and the gravity of his offences "breaks new ground".
"You had many fawning fans. That gave you power. You knew you could use that power to induce young female fans to have help satisfy your insatiable lust and take part in the sexual abuse of their own children," he said.
"Away from the highlights of your public performances lay a dark and sinister side."
Earlier, he said Watkins had a "high risk of causing emotional and sexual harm to children and to women".
Sentencing Watkins to a combined jail term of 29 years, he told him that he was being given an extended sentence.
That means he will serve two-thirds of the term behind bars before being released.
On his release in around 20 years' time he would normally have been on licence for the remainder of the 29-year term. The judge, however, added an additional six years on licence and told him: "Your total sentence, therefore, is one of 35 years."
Detective Chief Inspector Peter Doyle, who is heading up a hunt for potential further victims, described Watkins as a "committed, organised paedophile".
"My view of him as an individual is that he has shown no empathy, no sympathy or any remorse for what he has done," he said.
"It's as if he just doesn't care. He has shown no remorse at any time. In my view, that potentially makes him the most dangerous sex offender I have ever seen."
Mr Doyle said Watkins committed the worst kind of offending and specifically targeted babies.
He said: "Offending against children does not get any worse. We are not talking about children of any age here, we are talking about babies. I don't know what he is not capable of."
The abuse is thought to be so widespread that investigating officers have since launched a nationwide appeal for other potential victims to come forward - and are pursuing new leads after receiving a flurry of calls.
Mr Doyle told Sky News the force is working with Homeland Security in the US, Interpol and police in Germany to identify if any other children have been abused by Watkins.
"I think that it is likely that there will be further matters put to him, and others, in due course," he said.
The Independent Police Complaints Commission, which is investigating whether the force failed to act quickly enough after tip-offs about Watkins, has said it will now also look into South Yorkshire and Bedfordshire forces.
The IPCC said it is investigating the effectiveness of the responses by South Yorkshire, Bedfordshire and South Wales forces to reports of abuse made to them between 2008 and 2012.
Earlier today, the court heard Watkins spoke with a female fan from prison the day after admitting two counts of attempted baby rape and said he intended to issue a statement when he was sentenced saying it had all been "mega lolz".
In the conversation, Watkins denied being a paedophile and expressed exasperation at the way people had reacted to his guilty pleas.
Using text-speak, he said: "I'm going to put out a statement on the 18th just to say it was mega lolz.
"I do not know what everybody is getting so freaked out about."
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