A teenage murderer who is serving a life sentence after he killed a 15-year-old boy has been accused of dislocating a prison guard's shoulder.

Tremayne Grey, 19, is serving a minimum term of 14 years after he, along with four others, was found guilty of stabbing Jacob Abraham to death in Waltham Cross in December 2017.

Since he was jailed in July 2018, Grey has been serving his sentence at Aylesbury Young Offenders prison.

Grey was produced at Wycombe Magistrates' Court today (Friday) via videolink from prison, where he was charged with two counts of assault by beating of an emergency worker.

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Prosecutor Jacqueline Lyon told the court how on August 28 last year, Grey allegedly dislocated the shoulder of one prison guard and inflicted a head injury to another during a fight.

Reading out a statement from the officers, Ms Lyon described how one "heard a click" in his shoulder as it was dislocated, and how the other was unable to work for three days due to an injury to her head and ear.

After Grey pleaded not guilty to the charges, a trial date of December 12 was set. The trial will take place at Wycombe Magistrates' COurt.