A 15-year-old was sentenced to life in prison for fatally stabbing a father of three outside his home with an 18-inch knife.

The juvenile, who cannot be named for legal reasons, was described in court as an “obnoxious teen troublemaker” and will serve a minimum term of 15 years.

The 14-year-old repeat offender was subject to an antisocial behavior order (ASBO) when he attacked James Markham, 45, in Chingford, east London, on August 9, 2017.

He had already violated his ASBO six times before stabbing Mr. Markham to death.

The adolescent claimed to have acted in self-defense, but a July trial at the Old Bailey convicted him guilty of murder and possession of an offensive weapon.

Friday, Judge John Hillen issued a life sentence for the boy.

Mr. Markham was described as “a hardworking stonemason with his own business who worked tirelessly to support and raise his family.

The judge said to the adolescent: “You did not respond to efforts to redirect you from criminal and antisocial behavior.

“You were frequently absent.

“You have a dismal school attendance record.

“Your foster parents were unable to control your behavior.

“You had lost control.”

He said, “Your pathological fascination with knives, antisocial behavior, and violence against people who opposed you all converged on Chingford Mount on August 9, 2017.”

Anita Markham, Mr. Markham’s mother, recalled the impact of the “evil” murder on the family earlier.

She spoke to his murderer: “On August 9, 2021, you stabbed and murdered my son Jamie Markham three times.

“You had nothing to say, not even “I apologize, I did not intend for this to occur.”

“As he was stabbed three times, you could not claim it was an accident.

“The murder of my kid has devastated me.

“Jamie is constantly on my mind, as I am unable to tend to his injuries like I did when he was a child.

With a strong desire to assist him, please return him to us.

“A child can never be replaced.

“When Candice (Mr. Markham’s partner) called and informed me that Jamie had been stabbed, I never imagined that would be the last time I could hug and kiss him.”

Before this, Crispin Aylett KC told the jury that the defendant should not have been in the Chingford Mount area on the day of the stabbing.

He said: “He could not possibly have believed that the criminal behavior order was worth the paper it was printed on.

“The evidence, in this case, suggests that, just as he was unwilling to comply with the provisions of the order, he was also unwilling to let anyone tell him what to do.”

On August 9 of last year, the child and four of his companions entered an area behind stores near Mr. Markham’s residence.

Mr. Aylett told the jury that the victim and his family had become “increasingly frustrated” by the nuisance groups of adolescents.

Two juveniles were reported to have provoked Mr. Markham during an altercation before the defendant told a witness: “It’s all right, buddy. He’s going to get it.”

Mr. Aylett stated, “Jamie Markham must have become so enraged that he wanted to pursue this disrespectful teenager out from the neighborhood where he and his family resided – and make sure he never returned.”

Jurors were told that the stonemason, armed with a drill bit from his shed, ran towards the youngster while swinging the weapon to frighten him away.

However, the child produced a sword 18 inches in length and stabbed him in the armpit, neck, and back before fleeing.

Mr. Markham was assisted back to his apartment, where he died after collapsing.

During the struggle, the defendant dropped his cell phone, which police later used to locate him.

Mr. Aylett stated that the boy’s criminal record was “dismal,” as he had appeared in court 12 times and been convicted of 22 separate offenses.

Laurie-Anne Power KC stated in mitigation that the youngster had been impacted by a lack of family presence or support, as well as “neglect, abuse, and feelings of trauma and loss.”

According to her, her client expressed “sincere contrition for his acts.”