A sex attacker threw a kettle of boiling water over a fellow inmate in prison, a court heard today.

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 in 2006.

He admitted causing actual bodily harm during the incident in January at an earlier hearing at Banbury Magistrates' Court and was yesterday sentenced to two years.

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 assess how dangerous Cassidy was in March 2010.