At the end, Gerry's shirt is one color when he walks out of the courtroom and a different color when he talks to reporters outside.
When Gerry is released from prison, policemen standing behind him on the steps disappear and reappear between shots.
When Gerry speaks with the attorney, the guard behind Gerry changes position in each shot.
In court, Inspector Dixon states that he "never even spoke to Gerry Conlon". Some minutes later, when Gerry Conlon is being interrogated, the accused says "You told Inspector Dixon that you had committed a robbery" holding Gerry's statement. There's proof that Inspector Dixon and Gerry spoke, thus making his testimony in court false. Any defendant's attorney would have noticed this.
During the court scene, the judge uses a gavel to silence the court. British judges do not use gavels.
In the credits, Giuseppe Conlon's name is spelled "Guiseppe".
When Gareth Peirce approaches Dixon on the steps outside a building, the rank insignia on his epaulets denotes a Commander in the Metropolitan Police or Assistant Chief Constable in one of the other territorial police forces, and the oak leaf braiding on the peak of his cap runs along the inside and curved outside edges. Commanders and Assistant Chief Constables have only have single braiding on their caps' outer edge.
Scene of snow in the prison courtyard shows shadows cast by the sun to be overhead, which is not possible.
Gareth Peirce, a solicitor, addresses the court. At the time of the trial, only barristers had "rights of audience" to address the court.
In the Belfast apartment, Mr. Conlon throws some CDs in his case as he prepares to go to London to help Gerry.
When Gerry arrives in London in 1974, an early-1980s Ford Transit van and Ford Fiesta are visible.
During the riot, Gerry's sister and her friend are on the swings. Gerry's sister says, "Oh, my God," while mouthing something very different.
In an interior prison scene, a sound dolly and technician are visible on the left side for a few seconds.
When Paul and Gerry arrive in London, they walk the streets looking for Paddy's house. One street sign says 'Huskisson Street,' which is in Liverpool, not London.
A TV news report says Ardoyne is in West Belfast. It's actually in North Belfast.
During a TV news report, the presenter says she spoke to "Commander Robert Dixon", and Dixon appears on the screen with the caption "Inspector Robert Dixon". Commander is a higher rank than Inspector. At the time, Dixon was an Inspector, though he was promoted later on.