A senior garda, who drank whiskey to calm his nerves after accidentally reversing his car over a four-year-old girl, has been cleared of attempting to frustrate a drink-drive prosecution.

Detective Inspector Paul O'Brien from Moyville, Rathfarhnam in Dublin hit the young girl, who did not suffer any permanent injuries, when reversing out his driveway at 10.30am on 6 May 2013.

He had pleaded not guilty at Dublin District Court to consuming alcohol with intention of frustrating a prosecution under Section 4 of the Road Traffic Act.

Defence Counsel Martin Dully argued that Det Insp O'Brien had not been under suspicion of drink-driving when, following the incident, he drank a measure and a half of whiskey, and it was conceptually impossible that this was an attempt to frustrate a drink-drive prosecution being brought against him.

After hearing evidence from six witnesses and the defence submissions Judge Smyth dismissed the case.

The court had heard that the girl's paternal grandparents lived a few houses away from Det Insp O'Brien.

The family had planned a trip to the zoo and whiled a picnic was being prepared the girl went out to use her "flicker" scooter while her mother and father were on the same footpath and watched her.

The mother, Tracy Kirwan, told Judge Smyth she heard a bang and saw that her daughter had been "trapped underneath the back left reverse wheel".

The little girl was caught underneath her flicker under the back of Mr O'Brien's car, a grey Garda Ford Mondeo.

She said Mr O'Brien got out and was unaware the girl was under his car. Her husband David Kirwan lifted the rear of the car as Mr O'Brien moved it forward and the girl was taken out "screaming and crying".

She said the accident took place on the footpath and that her daughter had been going slowly on her flicker.

But she agreed with the defence lawyer that there was a wall about four feet in height along the path and a pillar which could have made it been difficult for her daughter to be seen.

David Kirwan said that after his daughter was lifted out from under the Mondeo, he shouted "you did not check your effing mirror" at Mr O'Brien.

"He said he did, I said 'you obviously did not, you are after running over my daughter'," Mr Kirwan told the court.

He also admitted that he had used colourful language when he was speaking to the defendant.

He and his wife brought the child to Tallaght Hospital to get her checked out; she suffered bruising and did not have any broken bones.

In evidence, her grandfather William Kirwan said he went to Mr O'Brien's home in the minutes after the accident but neither he nor his car was there.

He returned to his own house to call the gardaí and about ten minutes later Mr O'Brien arrived and told him "it was an accident".

About 20 minutes after the accident, Garda Donal Ashe spoke with Det Insp O'Brien in his house for about five minutes.

He told Judge Smyth that Det Insp O'Brien explained that he had been reversing out his driveway, had been looking both ways and could see people standing on the footpath up from him but no one else.

His view was obstructed by a tree at the entrance of the driveway and he immediately got out when he heard a bang and then noticed that the child was under the back of his car.

Gda Ashe agreed that it did not appear as if the defendant was under the influence of alcohol.

The incident was being treated as an accident and he went outside to wait for a breathalyser machine to be dropped around to him.

A short while later, he cautioned Det Insp O'Brien that he was going to breathalyse him and was told by him that he had "just taken a drink to calm his nerves because he was shook up by the incident".

He said Det Insp O'Brien's face was blushed red and his eyes were glassy.

Gda Ashe agreed with Mr Dully that the accident, in the context of Det Insp O'Brien having been driving an official Garda car, "was a pretty stressful situation".

Inspector Derek Maguire arrived and a sample of breath was taken which registered a fail and Det Insp O'Brien was arrested by Gda Supt Peter Duff at the house.

The defendant also told Gda Insp Maguire that he had "a measure and a half of Bushmills" after the accident. Another breath sample was taken from him which gave a reading of 29 mgs of alcohol per 100mls of breath, which is slightly over the drink-drive limit. 

Det Insp O'Brien did not face any other charges arising out of the incident, the court was also told during the hearing which concluded with the accused being cleared of the single charge brought against him.