Appeal judges yesterday authorised the Crown to hold a retrial in the case of a woman jailed for life after being convicted of shooting her policeman husband in the head.

The Court of Criminal Appeal rejected a plea that it should decide that Kim Galbraith was not fully responsible for her actions and find her guilty of culpable homicide. At her trial, Galbraith admitted she had killed her husband but claimed the physical, sexual, and emotional abuse she allegedly had suffered at his hands traumatised her so that she was unable to think rationally.

Yesterday, her defence counsel Margaret Scott quoted from the report of the trial judge, Lord Osborne, who said he had been ''both surprised and dismayed'' that the jury had convicted her of murder rather than the less serious offence of culpable homicide.

''I had no difficulty in regarding her evidence of the circumstances of her marriage and the experiences she described as credible,'' the judge said.

''Although, of course, the decision was one for the jury and not for me, I cannot avoid the conclusion that justice was probably not done in this case.''

However, Lord Justice General Rodger, who presided over yesterday's hearing, said Ms Scott was essentially asking the appeal court to substitute the view of the trial judge for the view of the jury.

He questioned how that could be done in a situation where Galbraith's credibility and whether the jury accepted her evidence were central to the case.

By the time Galbraith stands trial again, the appeal judges - Lord Rodger, Lord Penrose, Lady Cosgrove, Lord Nimmo Smith, and Lord Bonomy - will have issued a judgment redefining Scots law on the issue of diminished responsibility.

At the trial, Lord Osborne directed the jury that, before they could find Galbraith's responsibility for her actions was reduced from full to partial responsib-ility, they would have to decide that she was suffering from some form of mental disease - a state of mind bordering on but not amounting to insanity.

This direction was in line with the classic definition that had been followed since 1923, but at the appeal Neil Davidson QC, solicitor-general, accepted that the reference to mental disease was too restrictive and no longer appropriate.

If appeal judges simply substituted a culpable homicide verdict, substantial justice would not be done and the whole evidence of events leading to the killing should be considered by a new jury.

After the shooting of Ian Galbraith, 37, at the couple's cottage at Furnace in Argyll in January 1999, his wife originally claimed he had been killed by intruders who had also raped her. She later admitted to shooting him as he lay asleep in bed.

A date for a new trial has not yet been fixed.