A paedophile who ran children's homes in Wrexham has been jailed for life for sexually assaulting youngsters in a campaign of abuse spanning decades.
John Allen, 73, of Needham Market, Suffolk, had denied 40 counts of sex abuse against 19 boys and one girl in the late 1960s up to the early 1990s.
He was sentenced at Mold Crown Court on Monday after being convicted of 33 charges last week.
The judge ordered Allen must serve a minimum of 11 years in jail.
Before a packed public gallery Mr Justice Openshaw said: "There have no doubt been more prolific offenders but seldom can there be so many grave offences committed on so many victims over a long period of time, causing so much anguish and misery."
After sentencing, children's charity the NSPCC said Allen's "reign of terror over a dark period of several decades puts him high up the scale of the most prolific child abusers of recent times".
Allen was cleared of two charges last week. The jury was discharged on Thursday after failing to reach verdicts on four charges.
One alternative charge was dropped.
Meanwhile, a National Crime Agency spokesman denied it was investigating Allen in connection with supplying boys to child sex parties for prominent political figures at Dolphin Square in central London, which was reported in the Sunday Times.
"We do not have any evidence to suggest that John Allen supplied children for others," said the spokesman.
The case was the first prosecution following the Operation Pallial investigation into allegations of historical sexual abuse at children's homes, launched by the National Crime Agency (NCA) in 2012.
It identified 120 people as potential suspects and a further 12 people are due to stand trial for various offences in 2015.
Former hotelier Allen opened his first home, Bryn Alyn Hall in Llay, near Wrexham, in 1968, although he did not have any qualifications in childcare, his trial was told.
He set up the Bryn Alyn Community, which was to become one of the UK's largest providers of residential care, providing accommodation for children sent from about a dozen local authorities.
During the trial, which began in early October, the jury was told of Allen's previous conviction in 1995 for six counts of indecent assault involving repeated abuse of six boys dating from the 1970s.
More victims came forward following the publication of the Waterhouse report into abuse in north Wales care homes in 2001 and after Operation Pallial was set up.
One former resident at the Bryn Alyn children's home said living there "wasn't care, it was like hell".
'Shroud of respectability'
In an interview with BBC Wales, he explained how Allen had groomed him and gave him gifts before he abused him.
During sentencing, Mr Justice Openshaw said that the system of supervising and monitoring of Bryn Alyn was at the time wholly inadequate, boys did not complain because they knew it was quite pointless to do so, and that "gave the defendant the belief that he was untouchable".
He went on to say that there was a common theme of Allen targeting boys who were more susceptible to grooming with payments and presents given as "inducements" or to "keep them quiet".
After the hearing, Jon Brown, NSPCC lead for tackling sexual abuse, said instead of nurturing vulnerable children in his care, Allen abused his power and subjected them to "constant, horrendous sexual attacks".
"His manipulative and devious behaviour allowed him to hide behind a shroud of respectability while his helpless victims suffered intense emotional trauma," he said.
"Allen was able to evade justice for so long because he created an atmosphere of terror where no one was able to oppose him and where he effectively silenced his victims."