The murder of Vincent and Mary Cully is the most serious manifestation in recent years of a problem with which the courts are regularly faced - neighbours who have had a serious falling out with each other.

Last month a Garda Complaints Board tribunal recommended that Sgt Humphrey O'Leary be dismissed from the force after his neighbours, the Barretts, accused him of keeping their home under surveillance with a concealed video camera for four years.

The tension between the families began when Ms Nora Barrett organised a Tupperware party, but left Ms Marian O'Leary off the invitation list.

The Barretts vacated three of their front rooms because they felt their privacy was destroyed. When they took Sgt O'Leary to the Circuit Civil Court, he was ordered to apologise and remove the video camera.

Perhaps the best-known case of neighbourly disharmony in recent years involved Ms Myra Gallagher of Achill Sound in Co Mayo, who was sent to Mountjoy Jail when she refused to comply with a court order to get rid of her noisy rooster, Caoile, or to build a 6-ft wall between her garden and the house next door.

After nearly two weeks in prison, she purged her contempt and was released. Soon afterwards her rooster was killed by dogs and the wall was eventually built. However, she was back in prison in May this year after she failed to pay a £200 fine levied by the district court, which found her guilty of harassing her nearest neighbour by playing excessively loud music.

Psychologist and criminologist Dr Paul O'Mahony says the most docile of people can lose any sense of proportion when they are involved in a dispute with a neighbour.

"Because of the pressures of modern life, people look to their home as a haven. The social distance between neighbours is growing all the time. The home can become an isolated refuge, more like a fortress.

"If there's a problem between neighbours, the more aggrieved party can start to believe the other person has got the neighbours on their side and it becomes just a horrific burden that's weighing in on them."

THAT can be enough to cause someone like Seamus Dunne to explode and lash out. "We see more and more of these cases where people simply blow a fuse, in America in particular, and hit out in the most violent and horrific way.

"It's not always the aggressive, pushy types who do this. It's very often a person who's normally very controlled, very peaceful and somewhat shy," says Dr O'Mahony, adding that the courts are often a totally inappropriate setting in which to resolve disputes between neighbours.

"Often the underlying problem is seen by both sides as having being caused by the other. The courts take a side and hand out punishment in a way that is usually quite likely to exacerbate the sense of grievance and resentment, and even broaden it to society in general."

He proposes a parallel mediation service to which the courts could refer such disputes. "These situations are about human relationships and in many cases there is wrong on both sides eventually. Part of mediation is often to forget about blaming.

"A great difficulty with that kind of mediation service is that it can't impose solutions. However, there's nearly always someone in the dispute who is prepared to take a different route, whether it be a spouse or a son or daughter.

"Expert mediators who understand the kind of vicious circles that are involved in these disputes can sometimes cut through them and bring people together." Rather optimistically, Dr O'Mahony concludes, "in some cases the insights the parties gain can even turn them into friends."