A teenager who threw a kettle of hot water over an officer at a young offenders’ institute has been locked up for another four months.

The 17-year-old, who cannot be identified, was due for release from his previous sentence on December 20.

He will now have to serve just two months in addition before walking free.

Maidstone Crown Court heard how long-serving prison officer Graham Home retired on ill-health grounds after the attack at Cookham Wood in Rochester.

He was scarred and ended his 25-year career because of severe post-traumatic stress disorder.

The teenager, then 16, held a grudge against staff after being restrained by them and being moved to a new cell on a different landing after fighting with another inmate, a jury was told.

He was awaiting sentence for robbery and inflicting grievous bodily harm at the time of the attack on January 10. He was later sentenced to two-and-a-half years.

The victim said the teenager “exploded’ in anger” and threw the water from the kettle as Mr Home stood at his cell door. He turned away and jumped back.

The water spilled over his the back of his head, neck and arms, causing burns and blisters.

Other youths cheered, banged doors and shouted: “He’s done a guv.”

The youth, from London, was cleared of attempting to cause grievous bodily harm with intent. He had admitted assault causing actual bodily harm.

He was confined to a cell on the day of his attack after fighting with another inmate. Mr Home went to collect his dishes after a meal.

“I was assuming he was picking up his plate and bowl,” he said. “He then reappeared, shouted something at me and threw the kettle of hot water over me.

“I reacted by reflex. I turned my back and turned away to try and avoid what was coming at me. I believe the water would have hit me square in the face.

“It appeared immediately to be of a very high temperature because I was in a huge amount of pain pretty much straightaway.”

CCTV footage showed him jumping back from the cell door.

The court heard he has received commendations for both his courage and professionalism and been involved in many violent situations.

Sentencing the teenager to detention on Friday, Judge Philip St John-Stevens said prison workers had difficult jobs but the offence had to be viewed in context.

The water thrown was sufficient to cause injuries, he said. One burn was 9-10cm long and another on Mr Home’s forearm was 15x4cm.

“It is clear from the evidence you didn’t boil it ready to use as a weapon and there had been a period of time since the kettle had boiled, and you had no intention to cause or attempt to cause really serious injury,” said the judge.

He added that the physical and psychological effect on the victim was significant.