A filthy inmate "swilled" a female prison officer with urine and faeces that splashed into her mouth.
Disgusting crook Stephen Fletcher targeted the woman, who the ECHO has chosen not to name, at HMP Altcourse.
He called out "miss" to get her attention and when she turned to speak to him, took the lid off a container taken from the prison kitchens.
The 39-year-old, who has 45 past convictions for 90 offences, hurled the vile contents at close range in a "humiliating" attack.
He then walked off before the shocked victim and a colleague wrestled him to the floor, with Fletcher landing in his own mess.
Fletcher was jailed for six months on November 19 last year for threatening behaviour and possessing an offensive weapon.
Liverpool Crown Court heard he launched his attack 10 days later, in the prison's Valentines Red general population unit.
Michael Whitty, prosecuting, said: "This form of assault is known colloquially within the prison environment as either 'swilling' or 'potting'.
The officer had a good working relationship with inmates, but Fletcher moved onto the wing that day from the Furlong unit for drug users.
Mr Whitty said there was "disquiet" from some inmates due to his drug issues when the victim discussed Fletcher sharing a cell with them.
Shortly before 5pm, she and another female officer were unlocking cells ahead of the evening meal, when Fletcher approached.
Mr Whitty said: "She first noticed a mixture when it hit, as it landed on her body, landing on her crotch, thighs, as well as her legs and chest.
"Very quickly the smell revealed it was a mixture of urine and faeces and as the mixture fell from her and landed on the floor, she could see faecal matter among the mixture.
"Some of it having been thrown splashed up landed on her face. Sadly she was aware that a small amount went in her mouth."
The victim later went to a staff area, where she removed her trousers, and could see reddening to the skin.
Mr Whitty said: "She described it felt like her legs were burning. She removed her lower clothing and wrapped herself in a towel."
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However, she didn't get access to new clothes for an hour and a half, sitting in a relatively public office, adding to her trauma.
Mr Whitty said: "This aspect of the experience she describes being as degrading and horrific as what had happened on the wing."
The other 82 inmates on the wing were forced to return to their cells, where they remained locked up until the following morning.
Fletcher claimed he was paid to do it and if he refused he would have been slashed, adding: "You know what I'm like, I'm not that type of person."
But the next month he was overheard in a patient unit saying he "swilled a screw", adding: "They spoke to me like s***."
Officers attempted to interview Fletcher about the attack on January 1, but he refused to come out of his cell.
Fletcher, of no fixed address, pleaded guilty to administering a noxious substance.
His criminal record includes robbery, affray, eight common assaults and seven offences of resisting police.
John Rowan, defending, said Fletcher apologised to the victim and they had now "built a positive relationship with each other".
He said: "What this defendant wants known above all else is how genuinely sorry he is to the complainant and how absolutely disgusted he is in himself for the awful behaviour he engaged in on the wing in November."
Mr Rowan said Fletcher was "relieved and pleased" there were no lasting effects and the victim returned to work immediately.
However, he said Fletcher suffered "consequences" from other inmates and the governor of the prison.
His privileges were reduced to "a basic prisoner" for four and a half months, he spent 26 days in segregation, and after a prison adjudication 42 days were added to his sentence.
Mr Rowan said Fletcher was a dad-of-five, whose major issues began when his long term relationship broke down six years ago, and he left his family home.
He said his client couldn't see his children, shortly afterwards his mum died, his dad was a "seasoned heroin addict", and he fell into depression.
The lawyer said Fletcher turned to Class A drugs "to block everything out" and the "chef by trade" was now diagnosed and medicated for split personality disorder.
He said Fletcher's dad died while he was in jail, meaning he missed his funeral, but he had managed to remain drug free.
Judge David Aubrey, QC, said he couldn't be sure whether Fletcher was caught "boasting" about what he did to the victim.
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However, he said Fletcher had the intention of "injuring her, annoying or aggrieving her", and a desire to "humiliate, demean and distress her".
Jailing him for two years and two months, Judge Aubrey said: "The court reminds itself the container contained not only urine but faeces and it was a particularly unpleasant, demeaning and humiliating incident, which resulted in part of the container at the very least splashing into your victim's mouth."