The Court of Appeal in Northern Ireland has quashed a conviction for sexual assault of a child after finding the trial judge wrongly admitted evidence of the defendant's previous convictions.

The applicant, identified only as CT to protect the child's identity, had been found guilty by a jury at Antrim Crown Court on one count of sexual assault of a child under 13, contrary to Article 14 of the Sexual Offences (Northern Ireland) Order 2008.

The offence was alleged to have occurred between July and August 2017, when the complainant, his daughter aged 11 and a half, said he touched her vagina over her tracksuit bottoms while they sat on a sofa. She said he threatened to kill her mother and brother if she told anyone. The complaint was not made until August 2021.

At trial, the prosecution sought to introduce the applicant's previous convictions for sexual offences against his half-siblings, which dated back about 25 years before the alleged incident. The trial judge initially ruled this evidence inadmissible under the propensity gateway but, after cross-examination of the complainant and her mother, changed his mind and allowed the convictions to be admitted to correct what he saw as a false impression.

The false impression allegedly arose from defence counsel's questioning, particularly a question to the complainant: "...your father says he never touched you in an inappropriate or sexual manner and he would never have done that to you, is he right?" The judge considered the words "would never" as creating an impression that the defendant was a wholesome character who would not commit such offences.

The Court of Appeal, however, found the judge's analysis flawed. The court noted that the question was directed at whether the applicant would commit an offence against his daughter, not whether he would offend against anyone. Lord Chief Justice Keegan, delivering the judgment, said the judge's criticism of defence counsel was "misplaced" and the questioning did not create a false impression requiring correction.

Consequently, the court held that the bad character evidence should not have been admitted under Article 76 of the Police and Criminal Evidence (Northern Ireland) Order 1989 because of its adverse effect on trial fairness. The court concluded the error rendered the conviction unsafe and quashed it.

The Public Prosecution Service will now decide whether to seek a retrial.