THE Irish Prison Service has been forced to provide a round-the-clock security detail to a dangerous prisoner who has been in a coma for more than four months.

Geoffrey Evans, who is known as Ireland's first serial killer, has been unconscious and on a life support machine since he suffered a mass­ive heart attack on 18 December.

Evans then developed serious complications following a heart bypass operation at the Mater Hospital in Dublin, after being rushed from the prison cell he has occupied in Arbour Hill for the past 33 years.

Prison Service officials said they were under an obligation to provide a constant security presence for Evans in the unlikely event that he regains consciousness.

"It is an impossible catch-22 situation in that we cannot bring him back to prison as we could not provide the medical support he would require. And we can't leave him in the hospital without some kind of security," said a source. "Evans would have been categorised as an extremely high-risk offender and there is good reason why his repeated efforts to get parole have failed over the past decade."

Evans is considered highly unlikely to regain consciousness but the Irish Prison Service is still obliged to provide an extensive security presence. Up to three prison officers have to cover each shift at the Mater Hospital, in what is proving a major drain on resources for the Department of Justice.

The 66-year-old was considered the driving force behind a chilling plan to murder one Irish woman every week in the 1970s. Evans, along with his accomplice John Shaw, raped and murdered Dubliner Elizabeth Plunkett and Mary Duffy from Co Mayo before they were finally caught.

The two men were already wanted in connection with three violent sex attacks on women in Britain, from where both men originally came. When they came to Ireland, they decided to enact their sick plan to stalk, kidnap and murder one woman every week.

When Shaw and Evans were eventually arrested travelling in a stolen car in Co Galway, they ended up being questioned by Detective Inspector Gerry O'Carroll.

In a highly unorthodox interrogation technique, O'Carroll asked Shaw to kneel and pray with him for the dead women. The killer broke down and confessed.

Shaw was sentenced to life in prison for the murder of Mary Duffy and also received a 14-year sentence for rape in February 1978.

Evans, whose life now hangs by a thread, was jailed for life for the murder of Duffy and given a separate 20-year-sentence for rape.

A spokesman for the Prison Service declined to comment on the security arrangements for Evans, saying it is policy not to comment on individual prisoners.