A Perth man found guilty of sexually assaulting a young girl has had his conviction overturned because the charge did not exist when the alleged incident happened.
The man, known as SI, stood trial in the District Court on two counts of sexual penetration of a child under the age of 13 and two counts of indecently dealing with a child under the age of 13.
He was convicted of digitally penetrating the girl, but was acquitted of the three other charges.
It was originally alleged the crime was committed between December 31, 1992, and January 1, 1994.
However, the complainant's evidence at trial was the offence happened between 1988, when she was four years old, and 1994, when she was 10.
She believed it occurred at the "lower end" of that range, but could not be sure.
At the end of the prosecution case, the date on the indictment was changed to say it allegedly happened on a date unknown between April 24, 1988, and January 1, 1994.
The application was not opposed and was granted by the trial judge.
But the offence did not exist in the WA criminal code until August 1992, and that fact was overlooked at trial.
The Court of Appeal found today there was uncertainty about whether the appellant was convicted of an offence that existed at the time the alleged event occurred.
"In these circumstances, there has been a fundamental flaw in the proceedings, and consequently, a miscarriage of justice," the judges said.
"The appeal must be allowed, the conviction set aside and a judgment of acquittal entered."