A KILLER who murdered for a second time after being released from prison must serve at least 25 years before being considered for release, a judge decided yesterday.

Joseph McGinlay, 46, one of the few men in Scottish legal history to be let out of jail to murder again, was sentenced to life in March 1997 with a recommendation by Lord MacLean that he should serve at least 30 years.

As the law stood then, Lord MacLean took public safety into account when he made his 30-year recommendation. However, yesterday the judge had to consider McGinlay's case again under human rights legislation which requires him to fix a term the double-killer must serve as punishment and retribution for his crime.

The issue of public safety is now a matter for the parole board, and judges are not allowed to take that into account in fixing the punishment period.

Dealing with a series of lifers yesterday, the judge stressed that parole was a long and difficult process and prisoners would only be released if the parole board felt they no longer posed a public threat.

McGinlay was on weekend leave from Noranside Open Prison, near Forfar, when he strangled 22-year-old Mandy Barnett and stabbed her through the heart in her Edinburgh flat. When he was 18, McGinlay, from Dalmellington in Ayrshire, was jailed for life at the High Court in Glasgow in 1974 for the equally savage murder of 16-year-old Elizabeth Cassidy. He was also sentenced to 10 years for the attempted murder of her friend, Josephine Humphreys, 13.

After a jury at the High Court in Edinburgh found McGinlay guilty unanimously of murdering Miss Barnett, the woman's parents spoke of their relief that their nightmare had ended and questioned a system which allowed convicted murderers out to kill again.

Terry Barnett expressed the hope that McGinlay would spend the rest of his life behind bars.

The danger McGinlay poses to women was first highlighted at Ayr Sheriff Court in July 1972, when he was convicted of assault with intent to ravish and sentenced to two years residential training.

Lord MacLean told McGinlay in 1997 that Miss Barnett's murder ''ranks amongst the worst I have experienced both as a judge and as counsel''. The motive had not been explained but he inferred from all the evidence that there was some sexual motivation.

Explaining the 30-year recommendation, Lord MacLean said: ''Firstly, this is the second brutal murder of a young woman you have committed in your lifetime. Secondly, the second murder was committed while you were in fact still serving a life sentence.

''Thirdly, you may be very intelligent - the indications from the evidence was that that was the opinion some held of you - but you are also wicked and, in my opinion, you present a very serious danger.''