A TEEN murderer has been scolded by a judge for using a phone inside a prison where he is serving a life sentence.

Judge Michael Gledhill KC told 21-year-old Vainquer Muanza that he needs to ‘grow up’ and ‘learn to live in the prison’ after he was caught with a mobile inside HMP Bullingdon, near Bicester, on March 13.

Muanza, who claimed he had been threatened with a knife by another prisoner to look after the phone, was convicted of murder in July 2017, when he was just 14 years old.

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He is serving a life sentence with a minimum term of 16 years.

Adding another four months to his sentence at Oxford Crown Court on December, Judge Gledhill said: “I am going to take a lenient view of this case. It’s about time you get a grasp on the position you’re in.”

Opening the case, prosecutor Charles Ward-Jackson explained that Muanza was found with the phone after prison officers searched cells using ‘mobile phone detection equipment’.

The equipment flagged Muanza’s cell, giving a positive signal, causing the defendant to attempt to block his door with a chair.

However, he was detained and searched and during that time, the mobile phone fell to the floor. A USB power cable was also found inside Muanza’s cell.

Only four messages were found on the phone, the contents of which could not be accessed by police. Mr Ward-Jackson said: “We have to assume they were not sinister.”

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The defendant was interviewed before being moved to HMP Rochester. He stated he had been threatened by another prisoner to hide the phone and that he had only used to call a friend and a girl.

When asked why he didn’t report the prisoner, he said he ‘didn’t want to be known as a snitch’.

Muanza has been convicted in prison previously for assault by beating of a prisoner officer and violent disorder in October last year, leading to 13 months being added to his sentence.

Defending Muanza, Michael Nash said he is ‘trying to better himself’ in custody and has been in education, working towards the completion of his GCSEs.

He added that though the phone is a ‘security risk’, any sentence will impact his future parole hearings.

Judge Gledhill stated that the prisoner should be working towards being granted parole.

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“You do not do that by assaulting an emergency worker or by having in your possession a knife or an offensive weapon or having a phone,” he said.

“You know perfectly well that phones are not allowed in prison. You need to grow up and learn to live in the prison.”