Murderers who served time only to kill again on release

He was reprieved and served just under 12 years of a life sentence before being freed on licence in 1970. Within eight weeks, he stabbed a man to death in a brawl and received a second life sentence.

The parole board agreed to his release in 1998, after almost 40 years in total behind bars. However, in 2003 Forbes was jailed for 12 years, having turned to drug dealing. He died in 2008.

In 1967, George Emslie murdered a neighbour in Crosshill, Fife, with a shotgun, and was paroled after ten years in jail. In 1992, he axed his brother to death during an argument, and received a second life term.

In 1968, a teenage Alastair Thompson was convicted of murdering his grandmother in Edinburgh and given a life sentence. In 1992, aged 43, he was found guilty of murdering a man in Dundee, cutting up the body and dumping the various parts, receiving the nickname, the "Law Killer". He died in jail last year.

Joseph McGinlay, from Ayrshire, a convicted sex offender, murdered a 16-year-old girl and tried to kill her friend, 13, in a frenzied attack in 1974, and received the mandatory life term. In 1996, while on weekend leave from an open prison as part of his training for freedom, McGinlay strangled and stabbed a woman in her flat in Edinburgh.

William Ferris, 60, brother of Paul Ferris, the Glasgow underworld figure, was jailed for life at Northampton Crown Court in 1977 for murdering a man by stabbing him in a fight in a pub in Corby.

After release, and moving back to Scotland, Ferris "mistakenly" slashed and stabbed a teenager and set fire to his body in Irvine, Ayrshire, in 2003. The dead youth's brother, who had been involved in a fight with Ferris's wife, had been the intended target. He was ordered to serve 22 years before he could, again, apply for parole.