Judge Susan Denham's decision is significant because, although she did not express it in these terms, she takes seriously the notion that An Garda Síochána must be accountable for the actions of its members. Such accountability has been strenuously resisted within the force down the years, both by the garda representative bodies, and by garda authorities. In relation to the case under discussion here, the behaviour of the garda's top brass has been despicable. Although evidence was given during the 1997 trial about what had happened to her, although that evidence was accepted by investigating gardaí and although it was raised and expanded upon by the trial judge, Paul Carney, successive garda bosses and ministers for justice have resisted accepting any responsibility for what happened.

Even now, at this late stage, the current commissioner, Noel Conroy could help to reduce some of the damage done to the reputation of the force by settling out of court with this woman for a sum of money that might go some way towards acknowledging the grave wrong that has been done to her.

Before going any further, let's examine that wrong in more detail.

The woman, now a mother of seven children, is from Raheny in north Dublin. When the abuse started, when she was about 11 or 12, she immediately tried to have it stopped. On two occasions, she complained to her parents about what her step-brother was doing to her. On two occasions, they beat her and put her out of the house.

The abuse continued.

When she was about 13, in what must have been an act of the most enormous courage and bravery, she went to Raheny garda station to make a complaint. Two gardaí were present, a sergeant and the garda to whom she made a statement. He responded, according to evidence given in court in 1997: "Well, did you not enjoy that? Did you not feel good about all that fondling and what your brother was doing? You must have got something out of it?" The girl went home in tears, to another quarter-century of abuse.

In 1994, by now a mother herself, she got in touch with a social worker, who contacted the gardaí.

One of these, Garda Frances Withero, is a hero of this story. She found the woman's recollections credible and compelling, and pursued her case. It wasn't always easy. The woman was by now a timid and shy person and it was only over a period of time that she began to trust Withero, to see that not all gardaí were as callous as the man she'd met in Raheny.

Eventually, the whole story of her life came out. It included the information that one of her own children had been sexually abused.

Sentencing the woman's stepbrother to 15 years in prison in the summer of 1997, after he had pleaded guilty to rape, sexual assault and unlawful carnal knowledge (the rape conviction is now the subject of an appeal), Paul Carney was moved to restate what he called some old law, which makes it an indictable criminal offence for a peace officer to fail to act on a "credible complaint of felony". He quoted from an 1887 case called Creagh v Gamble: "A person against whom a reasonable suspicion of a felony exists shall be brought to justice. The peace officer is not only entitled, but bound, to arrest him." This principle of common law still existed more than a hundred years later, he said. It was a criminal offence for an officer "wilfully and without reasonable excuse of justification, to neglect a duty imposed on him".

And he concluded, in relation to the woman's case: "The effect of the rejection of the victim's credible complaints has been that she was incestuously abused for a quarter of a century longer than was necessary, that she bore a child by her step-brother, that she was abused while married, that she developed suicidal tendencies and that she was intimidated and beaten. She says herself that she has not had a life."

This is what An Garda Síochána has had on its conscience for more than 30 years now. Instead, however, of doing the decent thing and admitting responsibility for the ruination of a life that one of its members could have rescued, the force has resisted accountability all the way to the Supreme Court. Its main argument is that there has been an "inordinate and inexcusable" delay in bringing the woman's case.

On Thursday, Susan Denham dismissed that claim, pointing out that the woman's allegations have been known to gardaí since 1994, when she finally felt able to come forward with her allegations.

Denham also recalled that Paul Carney had appeared to accept during the 1997 trial that the woman had made complaints to Raheny gardaí, that they were credible and that they should have been acted upon.

Her decision is significant, not just for the woman involved, who must hope that somewhere in the upper echelons of the criminal justice system exists somebody decent enough to admit that terrible mistakes were made. It is important also because it reminds us that gardaí are there to fight crime and that they are legally obliged to take us seriously when we go to the station and make a complaint. Serving the public hasn't always been at the top of the Garda agenda and the Raheny case reminds us of what can follow when that duty is ignored.

Although, ultimately, the taxpayer will have to cough up for that error, it's a price worth paying.