A 45-year-old woman has pleaded not guilty to the murder of Englishman whose body was found in a slurry pit on a farm in Co Cork almost four years ago.

Una Geaney, of Mullinagleamig, Dingle in Co Kerry, but originally from Fermoy in Co Cork, pleaded not guilty at the Central Criminal Court sitting in Cork to a charge of murdering 37-year-old Gary Bull, at Shanlaragh, Dunmanway, Co Cork on 23 September 2007.

Addressing the jury of four women and eight men on the opening day of the trial, prosecuting senior counsel Tom Creed told them the nub of the State's case would be that there were three people directly involved in the killing of Mr Bull.

He said the jury would hear evidence that four people were shoved into a bedroom, while three others remained in another room with Mr Bull.

That he was standing and talking went the four went in, and when they came out he was dead.

There would be evidence, he said, that Mr Bull was assaulted seriously with an object like a big heavy mallet and that he died during this assault.

They would hear evidence that Mr Bull suffered multiple lacerations to the scalp and multiple fractures to the skull as well as fractures to his ribs, and bruising all over his body, especially his back.

The State will also argue that Mr Bull was removed by the three up to a shed where there is a slurry pit and the body put in there, only to be discovered by gardai a number of weeks later when - its alledged - someone to whom Ms. Geaney had spoken, went and told the gardaí.

By way of background, Mr Creed said a witness Claire Freeman will tell the court how she began a relationship with Mr Bull in 2000.

She will say that Mr Bull was a former heroin addict and that the relationship finished in August 2007 when she discovered he was having an affair with another woman.

Ms Freeman will say that she caught them out at the house in Shanlaragh.

Mr Creed said Ms Freeman will tell the court that Mr Bull could be violent towards her when he had drink taken and during one fight, he took a con-saw, reeved it up and started swinging it around.

Afterwards, she will say she noticed cuts to her clothes and a slight cut on her back.

Mr Creed told the jury that they will hear evidence that on Friday 21 September 2007 a birthday party took place at the house in Shanlaragh where a lot of drink and various drugs were taken.

The party continued on Saturday night and again on Sunday.

Mr Bull came and went several times but late on the Sunday arrived again with quite a bit of drink taken, spoiling for a fight and challenging everyone.

The jury will hear evidence that he exchanged a few blows with one guest outside the house and afterwards went to his land rover and started his con-saw and began waving it around.

Another guest picked up a piece of wood and struck him across the face, causing him to drop the con-saw.

He had a swelling to the side of his face and went into the house where he had an argument with his former parther Claire Freeman about the affair and she struck him in the face.

Mr Bull wanted to leave but Mr Creed alleges Una Geaney resolved he wouldn't leave, taking his car keys, as she feared he would come back with friends and cause more trouble.

The Prosecution will claim that she and two others didnt want him to leave - that they shoved the others into a bedroom, and that Mr Bull died after he was assaulted seriously with an object like a wooden mallet.

The case continues tomorrow before Mr Justice Paul Carney and is likely to last for up to one week.