Excrement covers the concrete walls of the prison cells like an uneven coat of paint. Cold air pours in through the smashed-out window, moderating the stench.

On the floor are two bare foam mattresses with clumps of dark woolen blankets on them. In one corner is a pile of more excrement, shredded toilet paper, broken egg shells and other garbage. In another is an open plastic chamber pot full of urine.

Besides two orange plastic mugs and water pitcher on the window ledge, the only other object in the cell is a black-beaded rosary, somehow immaculate and shiny, hanging from the light switch against the excrement on the wall.

This is how 363 convicted IRA terrorists have chosen to live for the past year: naked, with only the woolen blankets to wrap around them, in cells fouled with their own excrement and urine in the recently built, H-shaped cellblocks of Northern Ireland's sprawling Maze Prison near here.

The prisoners, mostly young Roman Catholic men of the Irish Republican Army who have been convicted of crimes ranging from assault and terrorist conspiracy to robbery and murder, are refusing to dress, use toilet facilities or clean their cells. They are protesting the refusal of the British government, which rules Northern Ireland, to classify them as political rather than criminal prisoners, because of their efforts to wrest Protestant-dominated Northern Ireland from Britain.

The conditions in which they live, although self-inflicted, have become a nagging problem for the British government in its ongoing propaganda war with the IRA in Northern Ireland. The European Commission on Human Rights is conducting a formal inquiry into the treatment of "H-block" prisoners in the Maze.

The IRA has successfully used its version of "the dirty protest" in the H-block to raise new money and political support from the Irish community in the United States.

Today, the Northern Ireland authorities, to present their side of the story, allowed reporters into the Maze Prison for the first time.

The tour came just before the official release tomorrow of a government report already publicized on alleged brutality by some Ulster police in their questioning of IRA suspects -- a second Northern Ireland issue that worries the British. Many IRA prisoners in the Maze were convicted on the basis of confessions obtained by Ulster police.

Maze Prison was built in the early 1970s to house the overflow of Catholic and Protestant demonstrators and terrorists arrested for sectarian violence in Northern Ireland.

The dozen reporters, photographers and television cameramen representing the media of Britain, Ireland and the United States were taken through the prison and allowed to tour H-block buildings and cells selected at random.

"We have been accused of taking people to parts of the prison we want them to see," said the prison governor, who, like the other Maze officials, asked that his name not be used for protection of himself and his family. He said he wanted the reporters to select the cellblocks "to dispel this. We can hold our heads high and assert we had no skeletons in our cupboard."

We went through one of the H-blocks occupied by "dirty protest" prisoners and inspected cells from which the prisoners had been temporarily removed minutes before our arrival. We were not allowed to interview any protesting prisoners.

As we walked through the cellblock, we heard them shout IRA slogans at us and bang loudly with their plastic cups on the green metal doors of cells we did not enter. "Long live the IRA," they shouted. "We are winning."

We saw one wing of H-block cells receiving its periodic cleaning, done every five to ten days, according to prison officers, while the prisoners are shifted to other cells. Workmen in plastic sanitation suits used high-pressure steam and garden hoes to clean the excrement off the walls and wash the urine off the floors.

Prison officials said the cells had no furniture because the protesting prisoners had fouled, smashed or burned it all.

We also toured other H-block cells where more than 600 Maze prisoners, including other IRA members and sympathizers, have accepted criminal status and are cooperating with prison authorities. Their neat, clean cells are furnished with beds, shelves, lockers, and bulletin boards with pictures and posters on them.

These cooperating prisoners have access to large playing fields, a new gymnasium and well-equipped vocational training and prison industry facilities.

The one complaint these prisoners made to the visiting reporters was their lack of physical freedom. To move from their 8-by-10 foot cells to the rest of the prison, they had to be accompanied by guards through a series of locked doors. They are driven to activities on buses that ply their way through many more gates in the 18-foot barbed-wire barriers that make the prison -- which holds half of Northern Ireland's total prison population -- a literal maze. The 146-acre prison, named for the area outside Belfast in which is located, has never had an escape from the H-blocks.

We also saw another segregated part of the prison where nearly 600 more men in "special category status" live in corrugated metal huts fenced with barbed wire that resemble prisoner-of-war camps.

Under the special category status, initiated in 1972, after a series of violent protests at another prison, both Catholic and Protestant militants convicted of offenses "connected with civil disturbances" were allowed to serve their sentences in these hastily built compounds. They wear their own clothes and are not required to do prison work.

The special category prisoners are grouped by the Ulster paramilitary organizations they belonged to and their huts bear IRA slogans or, in the case of the Protestant convicts, the names of World War I battles in which Protestant Ulster regiments fought.

The British government decided in 1976 to curtail the special category status as part of a stiffer effort to reduce sectarian violence. At the same time, extra visiting rights, home furloughs and early paroles were offered convicts who behaved well under criminal status in the new H-block cells.

Some convicted IRA terrorists who wanted to join their compatriots in special category status began in late 1976 to refuse to wear prison clothes and use only their blankets as body cover, although prison officers said they were otherwise cooperative.

Then, last March, according to prison officers, the protesting prisoners suddenly stopped using toilet facilities, refused to clean themselves or their cells, began smashing things and became very hostile.

Authorities say they believe this dirty protest has begun because the lesser protest had not attracted enough attention or sympathy for the IRA prisoners.

IRA spokesmen say through their "H-block information center" in Belfast that the prisoners were forced into the dirty protest by abusive guards who kicked over chamber pots in the cells and required prisoners to address them as "Sir" to gain permission to go from their cells to the toilets.

There are also 12 noncooperating Protestant prisoners. They still use prison toilet facilities and have not fouled their cells.

A Maze prison doctor said the dirty protest prisoners are "remarkably healthy" in part because their isolation does not allow contact with disease from the outside. However, several months ago, he said, protesting prisoners in two of the H-blocks were forced to shower and have their hair and beards cut to curb an outbreak of head lice.

Roy Mason, who has been the British government's Northern Ireland secretary throughout the Maze protest, has stated repeatedly that the government can never go back to giving prisoners special category status.

"Remember, we are fighting a terrorist group," Mason said on a recent BBC television program on which he defended the British policy against criticism from some U.S. congressmen.

"There is no question of giving back special category," Mason's top deputy, Don Concannon, said after our tour of the Maze. "There is no question of amnesty. The harder that is rubbed in the better. The protesting prisoners have told me, 'It's special status or nothing.' I have to say it will be nothing."