An inmate who slightly wounded a prison warder when he flung the contents of his mug him has been slapped with a fine and had his prison sentence lengthened.

Magistrate Consuelo Scerri Herrera heard how Joseph Bonnett, 37, attacked the correctional facility officer in April 2013 as he was unlocking the cell door following an argument about the inmate's refusal to clean his cell.

Since the accused failed to cooperate, the warder informed him that he would need to return into his cell until he could speak to his superior about the issue. As he turned to leave, the accused threw a glass of hot water at the officer's back.

As a result, the warder suffered superficial burns.

The warder explained that the accused proceeded to attack him and had to be restrained by the warder's colleagues.

The accused had claimed that prior to the incident, he had boiled the kettle to make some tea and insisted that the water he threw was tepid.

He said he had lashed out after feeling “frustrated” by the prison warder's actions. He alleged that the correctional officer had punched him after that, but provided no medical certificate to back up his claim.

In passing sentence, the court said that it had “no doubt that the accused's actions... were intended to cause offence and physically hurt the official, who was carrying out his duties.”

The accused was ordered to pay a €1,000 fine and had his prison sentence lengthened by four months.