A judge said it was "not appropriate to impose a whole life sentence" on triple killer Ian McLoughlin because of a European judgment.
A judge, who sentenced a triple killer to a minimum of 40 years in prison, was barred from giving a whole life term because of a European judgment that those sentences are in breach of human rights.
Triple killer Ian McLoughlin has been jailed for life with a minimum of 40 years at the Old Bailey for the murder of Graham Buck, 66, who was stabbed when he went to the aid of his convicted paedophile neighbour during a robbery.
Ian McLoughlin, who today admitted to the murder of pensioner Graham Buck, had killed twice before.
In 1984, he hit Len Delgatty, 49, over the head with a hammer several times after a row, and left his body in a cupboard. He was jailed for 10 years for manslaughter at the Old Bailey, reduced to eight years on appeal.
After his release, he went to live in Brighton, where barman Peter Halls, 55, offered him work. McLoughlin said he assumed Mr Halls was gay, and thought that he may be expected to sleep with him.
McLoughlin stabbed Mr Halls several times, and in 1992 was jailed for 25 years for murder, serving a total of 21 years behind bars.
Graham Buck's wife, Karen, said her life had been "turned upside down" by her husband's death.
Shortly before his murder, Mr Buck had returned for a long weekend in Poland, where he met his baby granddaughter for the first time.
Ian McLoughlin, who today admitted to the murder of a pensioner, said in a police interview he was "sorry" for the killing but did not regret the initial robbery.
McLoughlin, 55, who will be sentenced this afternoon, had met convicted paedophile Francis Cory-Wright in prison and turned up to his house claiming to need help setting up a charity supporting elderly ex-offenders.
But the 55-year-old, already a convicted killer, grabbed Mr Cory-Wright and demanded to know where he kept his "gold and silver".
The convicted paedophile, who was jailed for 30 months in 2011 for indecently assaulting a 10-year old boy in the 1970s, was tied to his bed and McLoughlin put silver family heirlooms into a pillowcase and demanded his bank cards and pin numbers.
Father-of-three Graham Buck, who lived two doors away from Mr Cory-Wright, went to help him after hearing shouting in his front garden.
McLoughlin said he was confronted by Mr Buck as he tried to flee the house and stabbed him.
A 55-year-old man has admitted to the murder of a pensioner who was stabbed after going to the aid of his neighbour - a convicted paedophile - during a robbery.
Ian McLoughlin appeared at the Old Bailey today where he admitted killing Graham Buck in Little Gaddesden, Hertfordshire, in July.
Mr Buck, 66, suffered fatal stab wounds when he responded to cries from the home of 86-year-old Francis Cory-Wright in the village near Berkhamsted.
Ian McLoughlin, 55, today pleaded guilty at the Old Bailey to the murder of Graham Buck, who was stabbed when he went to the aid of his convicted paedophile neighbour during a robbery.
Hertfordshire Constabulary has charged 55 year old Ian McLoughlin with the murder of Graham Buck in Little Gaddesdenon Saturday, July 13. Mr. Buck had been stabbed to death aftergoing to assist a neighbour who was being robbed.
Ian McLoughlin, who is also charged with robbery and possession of cannabis will appear before Hatfield Remand Court tomorrow.
He was arrested in Tottenham in the early hours of yesterday morning by the Metropolitan Police. The arrest was made following investigations by detectives from the Bedfordshire, Cambridgeshire and Hertfordshire Major Crime Unit.
Three further people were also arrested yesterday. Two of those have been charged with assisting an offender.