The judge, Mr Justice Drake, also "wrongly" told the jury that he had naturally formed his own views as to where the truth lay in the case, Patrick O'Connor QC, counsel for James Robinson, one of the accused, said.
Mr O'Connor detailed the criticisms on the fourth day of the appeal against conviction on behalf of the four men jailed for the death of the 13- year-old at Yew Tree Farm, near Stourbridge, West Midlands, in 1978.
Carl Bridgewater was killed by a single shotgun blast to the head after he entered the farm to deliver a newspaper.
Robinson, now 63, and cousins Michael Hickey, 35, and Vincent Hickey, 42, were jailed for murder. The fourth man, Patrick Molloy, died in prison in 1981 while serving a 12-year sentence for manslaughter.
Mr O'Connor told Lord Justice Roch, Mr Justice Hidden and Mr Justice Mitchell that Robinson was not only the victim of prejudicial evidence at his trial, but had been let down by the legal system.
"Substantial responsibility" lay at the door of the trial judge and the prosecution and defence lawyers, he said.
The "truth" comment made by Mr Justice Drake was wrong and inappropriate, he said, adding: "The Crown concedes that this sentiment would probably not be used today."
Mr O'Connor further alleged that the judge, prosecution and defence counsel had failed to secure a fair trial for Mr Robinson and that the case against him was "riddled with faults."
None of the Bridgewater Three - who are at present on bail - were in court yesterday.
They were released on unconditional bail in February after an independent forensic test revealed police had falsified a statement in a bid to extract a confession from the late Mr Molloy.
The appeal continues.Reuse content