Since 1998, there have been 92 murders that can be attributed to gangland feuds or had their origins in gang activity.

Only five of these cases have resulted in the perpetrator being convicted and gardai say it is highly unlikely the vast majority of outstanding murders will ever be solved.

Of the 141 people who have lost their lives to gun murder in Ireland over the last 10 years, just 14% of cases have resulted in convictions in court.

Gardai say they are being hampered by the unwillingness of witnesses to come forward and the lack of officers to proactively target gangland criminals.

There were 27 gun murders in Ireland last year, but only five prosecutions have been brought. Of the 17 gun murders so far in 2007, murder proceedings have been initiated in just one case. There were 21 fatal shootings in 2005 but just two convictions.

Only 40 gun murders have come before the Irish courts since 1998, with 21 convictions following, leaving a success rate of just over 50%. Many of the prosecutions that did succeed involved domestic or personal disputes, but it is in the area of gangland murders that gardai are really struggling to increase detection rates.

Of all the gangland slayings in the last 10 years, only the murders of Eddie Ryan, Kieran Keane, Brian Fitzgerald, Jason Tolan and Jonathan O'Reilly have resulted in convictions. In most of the other 87 cases, detectives believe they know who pulled the trigger, and why, but are powerless to bring prosecutions because criminals are forensically aware and destroy any evidence linking them to the crime scene.

There also exists a strict law of 'Omerta' in gangland, with criminals reluctant to go to gardai about the activities of their rivals. They instead choose to carry out revenge attacks, leading to cycles of murders like those seen in Crumlin and Limerick, where long-running gang feuds show little sign of ever ending. Independent witnesses are also often unwilling to go to the authorities with information because they fear threats and intimidation.

In the recent murder case involving Karl Breen, who stabbed his friend during a new year's eve party in a Dublin hotel, the main prosecution witness was forced to flee to Spain after being told he would be murdered if he gave evidence in court.

Meanwhile, the state's witness protection programme has been a total failure because of the unwillingness of anybody to participate in it. Under this programme, people who agree to testify in high-profile cases are given new identities and relocated abroad. But ordinary people do not want to see their lives permanently turned upside down and the programme has been almost totally shunned, except for a few criminals who have used it for their own ends.

The widespread availability of cheap firearms has also resulted in disputes now being settled with bullets instead of fists, as would have happened 15 years ago, so the murder rate is increasing rapidly. Most gangland killings happen because of drugs, and the huge sums of cash that can be accumulated from the drugs trade are making gang members only too willing to carry out killings.

Gardai say that, besides putting more officers on the streets and in specialist units to combat gang crime, there is little that can be done to reduce the current trend. One initiative that could work is using the non-jury Special Criminal Court in gangland trials, as suggested by Bertie Ahern last week. Most ordinary officers are in favour of this because they are frustrated the previous convictions of suspects and other intelligence cannot be raised in jury trials.

Informed sources say if the word of a senior garda was accepted against well-known criminals, it would go a long way towards addressing the current imbalance that exists between gun murders and convictions.