Britain’s youngest knife murderers, who killed a stranger in a brutal machete attack when they were aged just 12, have both been handed life sentences with a minimum term of eight-and-a-half years.

The killers, both from Wolverhampton, were convicted in June of murdering 19-year-old Shawn Seesahai, who was stabbed in the heart and suffered a skull fracture on the city’s Stowlawn playing fields on November 13 last year.

They were described at Nottingham Crown Court on Thursday as “the youngest knife murderers” and are believed to be the youngest defendants convicted of murder in the UK since Robert Thompson and Jon Venables, both aged 11, were found guilty in 1993 of killing two-year-old James Bulger.

Murder victim Shawn Seesahai (West Midlands Police/PA)

Mr Seesahai’s killers, both now 13, cannot be named because of a court anonymity order.

Both youths were allowed to leave the dock and sit in the back row of the court benches on Friday as High Court judge Mrs Justice Tipples began her sentencing by acknowledging the sentence being passed would be no comfort to the victim’s family.

The judge told the boys: “When you killed Shawn he was 19, starting out in his adult life with everything to live for.

“His parents have lost their son. His sister has lost her brother.

“What you did is horrific and shocking. You did not know Shawn, he was a stranger to you. You both killed Shawn in an attack that lasted less than a minute when he asked you to move (from a bench).

“I am sure you intended to kill him.”

The judge added that she could not be sure which of the boys had inflicted a 23cm-deep wound which almost passed all the way through Mr Seesahai’s body.

In a victim impact statement read to the sentencing hearing, the family of Mr Seesahai said they are haunted by thoughts of how scared he must have been when he was killed.

Police at the scene after the killing (Stephanie Wareham/PA)

Relatives of Anguilla-born Mr Seesahai described his murder as tragic, unexpected and senseless, and having been committed “for no reason at all”.

Both boys blamed the other for inflicting four wounds with the machete, after a dispute with the victim about sitting on a park bench.

One of the boys admitted possession of the knife prior to the trial, while the other was found guilty of the same charge when they were both unanimously convicted of murder on June 10.