Charles Crumley, 22, describes his life's work as fighting a "war of liberation against the British Army" in Northern Ireland. It is, he says, a "people's war."

Its major cost to him so far has been nearly three years of almost solitary confinement in a small cell during which he wore only a blanket or a towel and refused to use prison toilet and washing facilities.

British authorities arrested Crumley in December 1976. He was charged with membership in the Provisional wing of the Irish Republican Army, a banned organization that uses terror tactics to try to force the British out of the province and reunite it with the predominantly Catholic Republic of Ireland to the south. Crumley said he admitted the charge "to take the pressure off myself" after what he described as three days of intensive interrogation.

He was convicted 11 months later by a special court set up to deal with terrorist offenses in the strife-torn province and, a day later, joined 100 other "republican" inmates at the Maze prison near Belfast in what has become known as the blanket protest. Another prisoner "on the blanket" was Bobby Sands, the 27-year-old IRA "overall commander," who currently is reported near death from his escalated protest, a hunger strike in its 57th day.

Crumley, who was released from prison in August, is in this country -- illegally -- attempting to generate support for Sands. He was escorted to an interview Friday by two members of the Irish Northern Aid Committee, a militantly nationalist group based in New York that says it collects funds "for the dependents of Irish political prisoners." It is widely reported to be a conduit for funds to the IRA.

He is one of several former "blanket men" who have entered the United States clandestinely -- without a visa, withheld because of their criminal convictions or IRA membership. Officials of the U.S. Immigration and Naturalization Service have deported those they can locate.

Their blanket protest seeks to force Britain to grant political status to republican and "loyalist" prisoners rather than treat them as common criminals. r

From 1972 to 1976, Britain put convicted terrorists sentenced to more than nine months into special camps as "special-category" prisoners. A British official in Washington explained that the level of violence then was such that the prison system could not cope with the numbers involved. Separate accommodation in compounds was provided, prisoners were not required to work and had extra privileges like food parcels and visits.

This situation, the official said, caused the authorities serious problems of control and a commission recommended in 1975 that the special status be abolished. The government announced the phase-out of the status and a return to cell accommodation, which by then had been built.

Their cause has cost Sands and Crumley dearly and may yet cost Sands his life. Crumley said he and other "blanket men" spurned authorities' offers of substantial reductions in sentences and many prison privileges had they agreed to conform to criminal status.

For both men, for the three besides Sands on hunger strike, and for about 400 others who remain on the so-called "dirty protest," the notion of what they call "criminalization" of inmates' status is as unthinkable as it is attractive to the British authorities who introduced it.

At stake is not only an easier life in prison. More important to the IRA is its image in the half million-strong Catholic community. Catholics in Northern Ireland are outnumbered two-to-one by Protestants.

Catholic grievances over discrimination by the Protestant government in Belfast erupted in 1968 and Britain sent troops in 1969. More than 2,000 people have died in the continued violence.

The advantage of political status is that it confers legitimacy; criminal status erases it and erodes popular backing. "If [our] war is portrayed as a criminal war, the IRA as terrorists," people "will turn against" the IRA, Crumley said.

The present Conservative government in London, following the policy of the preceding Labor Party government, insists that political status for those convicted of criminal offenses is out of the question.

Last summer, the European Commission of Human Rights, in a case brought by four inmates at the Maze prison, found that they were not entitled to the status of political prisoners. It also found that the unhygenic conditions of the dirty protest "are self-imposed by the applicants as part of their protest" and that there is nothing "inherently degrading or objectionable" about requirements to wear prison uniform or to work.

Crumley, one of seven children whose home is in the rundown Creggan district of Londonderry, the city where two teen-agers were killed last weekend in clashes with Army troops and whose funerals spurred further rioting, says the "turning point" for him and his family was the 1972 "Bloody Sunday" protest in Londonderry against the policy of internment without trial. Army troops opened fire on Catholic demonstrators, killing 13 people.

Even his father, he said, who had served in the British Army during World War II, "could never understand how the British could do this." The younger Crumley said he soon joined Sinn Fein, the political wing of the IRA, and began participating in protests. He said his arrest prior to the one on the IRA membership charge, which he denies, consisted of troops rounding young men up "for screening," to try to elicit information on the sectarian violence.

Asked if he had a profession, he replied that he "never had that opportunity."

Crumley's three years of blanket protest, from the age of 18 to 21, he at first found "hard to accept." He "never personally appreciated it would go on so long," he said, but "as time went on, [it became] more and more a part of me." He "just couldn't do anything else."

The blanket protest escalated to the "dirty" level, he said, because of harassment and abuse from prison wardens. In the cells, which he said had no toilets, he described prison aides kicking over chamber pots they were meant to empty.

Cyril Gray, information secretary at the British Embassy in Washington, said "all systems are open to constant scrutiny" in British prisons and that the situation there "has been several times reviewed." In those instances where "any fault or cause for concern was established, steps have immediately been taken to remedy the situation."

The inmates, who Crumley said felt progressively more humiliated, felt they had "no alternative" but to decline to use sanitary and washing facilities.

"If you take a decision you have to stand by your principle," he explained. "Never back down."

The British, he said, will do so.

Last December, a 53-day hunger strike by seven jailed terrorists ended in a face-saving compromise.

Subsequently, Crumley said, Sands came to feel that he had been "personally deceived" over the alleged failure to implement the settlement and began the current strike March 1.

To British Prime Minister Margaret Thatcher's statement Tuesday reiterating the government's refusal to grant political status because "crime is crime is crime," Crumley suggested the prospect of further violence.

"What is going on now is a drop in the ocean" to what will happen if Bobby Sands dies, he said.

Britain's dilemma is that the same threat of violence, from Protestant militants, would apply in the event of a softening in London.