The fratricidal conflict in Northern Ireland has claimed hundreds of lives and millions of dollars in property damages over the past decade. Another victim of the violence has been the British system of justice. Frustrated by their inability to impose a political settlement on Ulster, the occupational forces have established a special standard of justice for those suspected of terrorist acts against the British troops.

Human-rights vioaltions, reported to us by a number of reliable sources, have put Northern Ireland on an unenviable par with some of the most barbarous regimes of communist commissars or tinhorn Latin American dictators. The British are trampling on the rights of Irish citizens in a manner reminiscent of Oliver Cromwell's iron-fisted rule more than three centuries ago.

As we have reported in the past, responsible sources have provided us with documented cases of repression and torture by British security forces. Respected international organizations have also compiled solid evidence of the inhuman treatment accorded Irish prisoners.

Despite all this and despite a campaign promise to speak out on human-rights violations in Northern Ireland, President Carter so far has ignored the protests of individuals and organizations concerned about the British army's abuses in the strife-torn land.

But now critics with more political clout have urged the president to speak out on the situation. Outraged by firsthand evidence they have obtained on a recent fact-finding tour of Ulster, Reps. Hamilton Fish (R-N.Y.), and Joshua Eilberg (D-Pa.), sent a private letter to Carter asking that he do something about human-rights outrages in Northern Ireland.

At the center of the controversy is the Long Kesh prison, a forbidding concrete fortress on the outskirts of Belfast. It is there that hundreds of Irish prisoners live in conditions of indescribable filth and physical deprivation.

Most infamous of all is the "H" Block, or "hell block," as it is called by the prisoners. Its inmates, known as "blanket men," have been clothed only in blankets and towels since 1976, when British courts declared that IRA suspects were no longer to be given special treatment as political prisoners.

The few outsiders who have been allowed into H Block report that the walls are encrusted with rotting food, the floors are littered with excrement and an overpowering odor of decay is all-pervading.

One respected religious leader compared the horrors of H Block to the "tiger cages" of Vietnam, where American-trained South Vietnamese captors interrogated prisoners, or the North Vietnamese torture cells where American POWs were brutally mistreated.

Indeed, Rep. Fish concluded that the conditions at Long Kesh are "worse than Saigon in 1968."

Hundreds of Irish prisoners in H Block, many of them still in their teens, were put there after signing confessions often extracted under torture by British security forces. Under the emergency suspension of Britain's honored legal system, anyone arrested may be held incommunicado for as long as seven days without even a formal charge.

It is estimated that perhaps 75 percent of the political prisoners in Long Kesh have been convicted by uncorroborated statements or force confessions made in Stalin-like kangaroo-court prodecures.

British officials tried to persuade the visiting congressmen and other dignitaries that Long Kesh is a model prison whose inmates are treated with dignity in an up-to-date, humanely run facility. Almost no one swallows the official British line, however.

'They tried to give us a Cook's tour," confided one congressional source, who was shown model facilities on the outer perimeter of Long Kesh.

Several Ulster women have come to us with pathetic tales of the mistreatment being visited upon their husbands and sons, some as young as 16. They have been begging Congress for help, believing along with thousands of Northern Irish that only U.S. intervention can bring end to Ulster's horrors.

An ad hoc Irish committee of 119 members has been formed in Congress. But the committee's attempts to publicize the outrages being committed in Northern Ireland, along with the efforts of the Iriah National Caucus have been blocked by House Speaker Tip O'Neill and other congressional leaders who are reluctant to offend our British ally.

The initial letter from Fish and Eilberg was bucked to the State Department, whose bureaucratic response infuriated the lawmakers.

They fired off a second note to the president, in which they cited "incontrovertible evidence that the Northern Irish people, both Catholic and Protestants, earnestly and sincerely plead for U.S. assistance in achieving political and social stability."

Drawing a parallel to the Mideast situation, the congressmen told the president: "Your achievements at Camp David could be repeated in the resolution of this turbulent situation."

Footnote: Rep. Mario Biaggi (D-N.Y.), chairman of the ad hoc committee, will visit Northern Ireland in a few weeks to plead for the organization of an international peace forum for unhappy Ulster.