There is no dispute about the movements of Owen Gaffney in the earlier part of the day in question. He got up sometime that morning, Sunday, 17 February 2008, and went to play a football match with his club, Mourne Celtic. He played in goal for the team. The game kicked off around midday. After the final whistle, he made his way home to his flat at Basin Street. He lived there with his mother Fidelma and sister Vicky. Gaffney was 18 years old at the time and had been resident in the flat for most of his life. The flats are part of a large complex of public housing units, near St James' Hospital in Dublin.

He estimates that he arrived home at around 2pm. Then he went to bed, taking off the top he wore, but leaving on his tracksuit bottoms. His bedroom contained, among other things, a single bed, and a TV. There was also a large flag and other effects, which, the Circuit Criminal Court heard last week, were associated with the promotion or use of cannabis. Gaffney says he used to smoke the drug, but didn't do so on the day in question.

Some time later in the afternoon, most likely around 5pm, a number of garda officers entered his bedroom. What happened thereafter is the subject of dispute, which has ultimately led to the trial of four officers charged with assault causing harm. Three of the officers are also charged with false imprisonment.

According to Gaffney, he awoke initially when he thought he heard the door to his room creak, but there was nobody there. He dozed back down into the shallows of sleep.

Then, "I sensed that there was somebody there," he told the court last Wednesday. "Garda Sean O'Leary was standing next to me. He had two batons in his hands. He hit me. I was dazed. They all started hitting me. There was more than three of them in the room."

He says he immediately identified Garda Seán O'Leary. "I knew him from driving around, he was based in Kilmainham [station]. He had arrested me before.

"He hit me with the baton. [Garda] Eoin Murtagh hit me on the arm. They picked me up and smacked me head off the end of the bed." He says he was then thrown onto the floor, where Eoin Murtagh kicked him on the chin. Later, the court heard that in five statements about the incident provided to the Garda Ombudsman Commission, the complainant had never identified Murtagh as specifically assaulting him in any manner. The other two officers on trial are Alan Conlon and Claire Delaney.

The assault, according to Gaffney, lasted between five and seven minutes. At one stage, he says his mother appeared at the door. "Me ma came running in when she heard them hitting me. A garda had me mother by the neck against the mirror. I said, 'Seán, please, not in front of me ma.'"

The court has heard that the prosecution will show that Fidelma Gaffney was taken into the bathroom, and kept there against her will while the assault on her son continued.

Eventually, the beating stopped. "They all left and me ma came running in crying," Gaffney told the court. "I had baton marks, a swollen nose, a busted lip, there was something wrong with my head, broken skin in my arms."

He went to St James' Hospital to have his injuries treated and was released later that evening.

In the course of cross-examination on Thursday, it emerged that the gardaí on trial have presented a version of events which is at complete variance with how Gaffney remembers the few violent minutes.

Counsel for O'Leary, Hugh Hartnett, put it to the witness that he was actually sitting on the side of the bed when the gardaí entered his room. The lawyer suggested that Gaffney jumped up, threatened to kill the gardaí and started lashing out violently in a struggle that had several officers on the ground with him.

"If that happened, why wasn't I arrested?" the witness asked the lawyer.

Owen Gaffney is now 21. He told the court that he left school at 15 or 16. He spent seven months on a Fás course, but otherwise he hasn't worked since completing his formal education.

Proceedings in the trial got off to a slow start. The jury of six men and six women was sworn in on Monday. The prosecution opened its case on Tuesday. Gaffney's direct evidence was heard on Wednesday, and he was cross examined on Thursday. The only other evidence heard during the week was technical detail of the scene supplied by an officer from the garda ombudsman's office on Wednesday morning. An adjournment was granted on Friday morning, which put paid to proceedings until this week.

The wheels of justice grind at such a pace. On Tuesday, for instance, the court got under way at 11.48am, when it is scheduled to start at 11am. After lunch on Wednesday, it didn't reconvene until 2.28pm. Hearings are scheduled for four hours a day, but between the jigs and the reels this can often be reduced to as little as three.

By the middle of the week, it was becoming obvious that Court 15 was not big enough for what might otherwise have been a routine assault charge in the circuit court. There simply wasn't enough room for all the lawyers.

The four defendants are each represented by one of the country's leading criminal lawyers. Cramped together on the bench are senior counsel Hartnett, Isobel Kennedy, Patrick Gageby and Brendan Grehan, all from the heavy artillery division of the law library. Sitting just across from them is one of the state's main prosecutors, Tom O'Connell. On the bench behind the senior counsel sit up to six juniors. Facing this phalanx of lawyers are five solicitors. Justice, as might be gathered, does not come cheap and easy.

On Thursday, proceedings moved to the more spacious Court 13. The lawyers breathed again, having been afforded the room to flex their gowns.

Hartnett was the first lawyer to cross examine the witness. When he rose to begin his questioning, he didn't tell Gaffney who he was, or which of the accused he was representing. At one stage, Gaffney replied to a question saying, "to be honest, barrister, I'm not sure".

The lawyer brought him through a number of incidents which involved altercations or threatening or abusive behaviour.

He did concede that he has some form. "I wasn't an angel when I was a teenager," he said. In total, he has 27 convictions, many of them minor matters, but including one in which a garda sustained a broken or fractured jaw. For that offence, he was sentenced to 240 hours of community service, but didn't complete it. As a result he was jailed for three months.

He denied in court that he had assaulted the garda in that incident.

"I pleaded guilty to that because my father said if I pleaded guilty I would get, what's it called again, the probation act, or community service."

He denied that he had been abusive to gardaí in a number of incidents. "When they do be abusive to me, I do be abusive back to them," he said.

He was asked about an incident alleged to have occurred on 16 February, 2008, the night before the gardaí ended up in his bedroom. He denied having knowledge of any such incident.

On Friday, the prosecution counsel Tom O'Connell said a matter had come to his notice which was prompting him to apply for an adjournment until Tuesday morning. Four days into the trial, only one of the four defendants has completed cross examination of the chief witness and complainant.

The trial before Judge Desmond Hogan resumes sometime after 11am on Tuesday. It was pencilled in for two weeks, but very often these predictions are little more than a shot in the dark.