The minimum sentences given to Britain’s teenage knife killers for the murder of Shawn Seesahai will be reviewed by the Court of Appeal following claims the sentences were overly lenient.

The boys, now 13, were 12 when they attacked Mr Seesahai with a machete on playing fields in Wolverhampton on November 13 last year.

They were both found guilty of murder in June and sentenced to life imprisonment with a minimum term of eight-and-a-half years at Nottingham Crown Court in September.

In a statement confirming that the boys’ sentences would be reviewed, a spokesman for the Attorney General’s Office said: “These sentences have now been referred to the Court of Appeal under the Extremely Less Sentencing scheme.”

The scheme allows relatives, victims and members of the public who believe sentences are unreasonably low to ask the Attorney General’s Office to review cases relating to a range of specified serious crimes and decide whether to refer these cases to the Court of Appeal.

Mr Seesahai was stabbed in the heart and lungs and suffered a skull fracture on the Stowlawn playing fields; One of the wounds covered almost his entire body.

His killers were described as the “youngest knife killers” at the time of their sentencing 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 of murder by two years in 1993. ex-James Bulger.

Passing sentence, Mrs Justice Tipples told Mr Seesahai’s killers: “What you both did is appalling and shocking. You didn’t 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 park bench).

“Shawn’s parents, sister, and friends did not deserve to lose him from their lives and experience the never-ending pain, suffering, and loss you have inflicted on them.

“It is clear that the sentence I decided to impose cannot justify this. What you did in those few moments changed your life forever.

“You will both have to live with the consequences of your actions for the rest of your lives.”

The judge added that he was not sure which of the boys had inflicted a 23cm deep wound with the machete.

In a victim impact statement read at the sentencing hearing, the family of Mr Seesahai, 19, from Birmingham, said they thought how frightened he must have been when he was killed.

Relatives of Mr Seesahai, who was born in Anguilla, said the murder was tragic, unexpected and senseless, and that it was committed “without any reason”.

Both boys denied murder and accused the other of inflicting four wounds with a machete.

One of the teenagers admitted to possessing the knife before the trial, while the other was unanimously convicted of murder and found guilty of the same charge on June 10.