Breaches of child abuse guidelines laid down after the Cleveland scandal did not make the evidence so unreliable as to be unfair, the judges ruled.
But lawyers argued a flawed investigation and the unreliability of child witnesses made the convictions unsafe and unsatisfactory and said they would consider a further appeal.
The freed man, who cannot be named for legal reasons, joined in criticising social workers whom he claimed had prompted the allegations of a paedophile ring operating in Pembrokeshire, west Wales.
Speaking outside the High Court, he said: "I know they've got jobs to do, but why don't they do it properly? It's been hell. Half an hour ago I was the scum of the earth. Now I'm a human being again." He and four of the others were convicted at Swansea Crown Court last year of conspiracy to abuse. The sixth man was cleared of conspiracy but found guilty of buggery with his two children. The men received sentences of between 5 and 15 years.
At the end of the trial, Ray White, Chief Constable of Dyfed-Powys, called the inquiry a "model of perfection".But the appeal heard claims, at least partly accepted by the Crown, of children coached before making video statements, "contamination" of evidence where the children were allowed to discuss the claims between themselves and confusion between therapy to help the children and investigation of their claims. However, Lord Justice Swinton Thomas, sitting with Mr Justice Waterhouse and Mr Justice Harrison, said it was up to the jury to decide whether children were telling the truth once it was established that they knew right from wrong and understood the questions.
The freed man was released after the judges ruled medical evidence concerning his two-year-old daughter should not have been permitted at the original trial. As the jury were likely to have relied on it, the conviction was unsafe. But although some of the children's claims were "fantasy", there was evidence of adults bringing their children to group abuse sessions, the judges said. They were not persuaded the other convictions were unsafe.
Relatives of the unsuccessful appellants left the London courtroom in tears. The wife of one man, convicted of abusing two sons by his first marriage, said: "There's no such thing as British justice."
The stepsister of one of the men said: "This has been a con from start to finish. They're all covering each other's backs."
Paul Settatree, solicitor for one of the men, said: "This has resolved nothing. There have been lots of erudite legal points but justice has not been done. It hasn't looked at the question of the extent to which children are susceptible to suggestion."
Dewi Evans, Dyfed's director of social services, said the outcome was a vote of confidence for the department, although errors had been made. The child protection committee would examine refining procedures and improving training.Reuse content