A sentence closer to 10 years would have been more appropriate, Brian Kerr QC, said in opening a review of the sentence given to 24-year-old Susan Christie, who killed Penny McAllister in March 1991. Christie was having an affair with her victim's husband, Capt Duncan McAllister, who was serving in Northern Ireland with the Royal Signals Corps.
The trial was described as a very important case by Northern Ireland's Lord Chief Justice, Sir Brian Hutton. He said sentencing in cases involving diminished responsibility was one of the most difficult tasks that judges faced.
The five-year sentence had been imposed for manslaughter after Christie had been found not guilty of murder.
She stabbed Mrs McAllister as they walked in a forest. Christie claimed she had been suffering from acute stress and mental abnormality at the time of the killing.
Mr Kerr said that probably the most important factor was what degree of residual responsibility remained after this had been taken into account. There were aggravating features, he said, including the degree of residual responsibility, the force used and the innocence of the victim. These more than offset mitigating factors such as the accused's youth and previous good record.
Mr Kerr said a considerable amount of premeditation had been evident. It had been expressly held that premeditation, even where it was the result of a depressive illness, could nonetheless attract a longer sentence.
Mr Kerr said one factor that had influenced the Attorney-General was whether the sentence fulfilled the legitimate expectation of society. Sir Brian said Christie suffered from a mental abnormality induced by disease, a factor that might not have been appreciated by the public.
The hearing continues today.