A SEX attacker threw a kettle of boiling water over a fellow inmate in prison before calmly walking away, a court heard.

Oxford Crown Court heard John Cassidy, 29, threw the water over an inmate at Bullingdon Prison because of rumours he had tried to rape a woman.

Cassidy, formerly of Samphire Road, Blackbird Leys, was jailed for an indefinite period of time last March after attacking four lone women in secluded spots in Oxford during a five-day spree in 2006.

He admitted causing actual bodily harm during the incident in January at an earlier hearing at Banbury Magistrates' Court.

Jonathan Stone, prosecuting, said: "He filled a kettle with boiling water from an urn.

"He then approached cell 141 and noticed that the door was slightly ajar.

"The victim was standing on a chair reaching up on the top of the cupboard at the time.

"Mr Cassidy took the lid off the kettle and threw the boiling water across the victim, causing burns to the left side of his face.

"Mr Cassidy then calmly, simply, walked back to his cell."

Henry James, defending, said: "He is ashamed of what he has done. He is deeply sorry."

Mr James said the parole board would have to assess how dangerous Cassidy was in March 2010 and added this attack could extend his time in jail.

Sentencing Cassidy to two years in jail, Mr Recorder Harold Persaud said: "This was a premeditated and unprovoked attack on someone you knew was not in a position to avoid the hot water or defend himself."