A man jailed for a series of armed raids on betting shops threatened to stab a prison officer after drinking illegally brewed alcohol, a court has heard.

Dean Smith, 25, who was an inmate at Wayland Prison serving a nine-year stretch for betting shop robberies, was drunk after he had been drinking hooch - illicit alcohol brewed in prison.

King's Lynn Crown Court heard Smith was behaving aggressively, resulting in other prison officers being called to assist.

John Morgans, prosecuting, said a female prison officer managed to help get Smith back into his cell.

But as she was escorting his cell mate out, Mr Morgans said Smith picked up a weapon - a toothbrush handle with a razor blade melted into one end.

Smith raised the improvised knife above his head before saying "I will stab you" to the prison officer.

Mr Morgans said other prison officers intervened and managed to disarm Smith, although the victim fully believed the threat and thought she was going to be stabbed.

Smith, of Onley Prison, appeared at court on Thursday (June 10) after having previously admitted common assault of an emergency worker on June 16 last year.

The defendant had also admitted a charge of unauthorised possession in prison of a knife.

Stephen Spence, mitigating, said Smith had been sent to segregation following the incident before being returned to the general prison population as he was not considered a threat either to prison officers or other prisoners.

He said the knife had not been used for the infliction of violence on others but had been an item used by Smith "in order to self-harm".

Mr Spence urged the court not to "crush" him with any sentence that was imposed following his guilty pleas.

Sentencing Smith to a total of 21 months imprisonment, Recorder Oliver Sells QC said the courts "took these matters seriously".

Recorder Sells added that prison officers were there "to be protected in their work".