James Markham, 45 years of age was stabbed in the neck and left side of the body in August last year. He died at the scene a short time later. The teenager accused of murder appeared in court on Tuesday and pleaded not guilty to murder and possession of a blade in a public place.
Judge Anuja Dhir QC remanded the teenager into custody until a trial, due to begin on June 27 next year.
Passing sentence at the Old Bailey, Judge John Hillen told the boy he was “out of control”.
“You had not responded to attempts to divert you away from crime and antisocial behaviour,” he said.
“You regularly went missing. You have a low attendance record at school.
“Your foster parents could not prevent your behaviour.”
Markham was killed after a confrontation with a group of youths. He had been frustrated by the anti-social behaviour of youths in the area and was forced to intervene. His wife Candice was able to hear the fight but did not know that her husband had stepped into it and ended up dead.
The teenager involved in the murder of James Markham was sentenced to 15 years in jail. He was found guilty of murder and other charges, including possession of an offensive weapon.
Although he cannot be named for legal reasons, the conviction will be a comfort to his grieving family.
The 45-year-old father of three was stabbed to death as he attempted to protect his daughter. He had spotted two teenage boys in the area shouting at Chloe and confronted them.
He had a drill bit in his hand and stabbed them several times. One of the teenagers, a 14-year-old, had flouted a previous criminal behaviour order and was able to stab the father-of-three three times.
The Met has informed the next-of-kin, who specialist officers are assisting. The reports say that the father of two was trying to protect his daughter when he was stabbed by the youths. He was attacked after confronting a group of youths, according to Det Insp John Marriott. Anyone with information is urged to call 101.

How James Markham was murdered
The stonemason had been banned from the area after a row with his friends. They had also been arguing with Mr Markham. When Mr Markham saw the boys, he snapped. He then rushed out of his shed at the back of his flat and brandished a significant drill bit.
Jamie Markham was a stonemason who weighed 8 stones and stood five feet tall. The teenager pulled out an 18-inch knife and stabbed him three times. A neighbour then helped him back to his home.
Jamie Markham was a 45-year-old stonemason. He had three young children and worked hard to support his family. The prosecution described him as an “out of control” troublemaker, but it was unclear what prompted the teen to attack Mr Markham.