More than three years after the Omagh bombing, the attack that claimed 29 lives in a late summer afternoon continues to generate shockwaves.
Although the Police Service of Northern Ireland (PSNI), formerly the RUC, strongly attacked the draft report of the Police Ombudsman yesterday, the findings reverberated through the system.
They posed the most fundamental of questions about the competence and, above all, the integrity of policing structures, leaving many observers shocked and scandalised.
While nationalists and Catholics have always been critical of the RUC, most Protestants and Unionists have doggedly clung to their faith in the force, and in particular its Special Branch, as a bulwark against terrorism.
The thought that warning signs that might have prevented the attack were not acted on will deal the most severe of blows to trust and confidence in the RUC and the intelligence system.
While many are prepared to accept that intelligence and dealing with terrorist organisations involves questionable activities, the idea that Omagh's 29 deaths may have been preventable is among the most damaging and devastating allegations ever levelled at the police.
The attack, the work of the Real IRA, is regarded as one of the worst atrocities of the Troubles, partly because of the heavy death toll and partly because it took place at a time when violence was declining.
The initial highly combative responses from both the PSNI and the Police Federation serve notice that a head-on clash is about to take place between them and the Police Ombudsman.
While the PSNI is clearly intent on challenging the report almost on a line-by-line basis, the fact that two warnings of republican activities were received will undoubtedly damage the RUC's reputation.
The Ombudsman, Mrs Nuala O'Loan, has previously come under fire from Unionist politicians. Her office has not been long in existence, and she is regarded as an independent figure who has not been absorbed into the system.
Her report's clear implications that important points remained hidden in the aftermath of the bombing will heighten existing suspicions that a culture of secrecy and denial has survived the programme of police reforms.
The sense is that some important elements in the security sphere are concerned not with making a new start but with concealing past misdeeds and mistakes. While such a belief is widespread among nationalists, the political pain will be sharper to Unionists.
Policing continues to be among the most sensitive issues in the Northern Ireland peace process, with much raw hurt still evident among supporters of the RUC concerning its transformation to the PSNI.
On the nationalist side it remains an unresolved issue, with the Social Democratic and Labour Party joining the new Police Board but Sinn Fein refusing to do so. Republicans were claiming last night that their stance has been vindicated by the Omagh revelations.
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