N. Ireland police combat Mafia-like gangsterism of paramilitaries

The police in Northern Ireland have formed a special investigative team to combat racketeering by paramilitary organizations.

Chief Constable Sir John Hermon said that detectives are leading a campaign against extortion, tax swindles on building sites, terrorist ''front'' organizations, protection rackets, and illegal collections.

Large sums have been obtained by the paramilitaries to finance a campaign of violence, including money from holdups and bank robberies, particularly in the Irish Republic.

Sir John Hermon, a blunt-spoken Ulsterman who rose through the ranks to become chief constable, knows intimately the atmosphere of terrorism in which his forces have to operate. He told Belfast businessmen at a civic lunch:

''What we are faced with here is Mafia-like gangsterism of the very worst kind and all the viciousness that goes with it. The money that the paramilitary organizations steal or extort is blood money because it finishes up in blood. It buys guns, it buys bombs, it keeps in comfortable power the godfathers who organize and direct death and destruction.''

The new drive has been made possible by information obtained by police about the activities of both Republican and Loyalist (loyal to Britain) paramilitaries. This year there has been an unprecedented flow from within the terrorist organizations.

So far 16 Republican informers have given valuable information. Eleven members of the Provisional wing of the illegal Irish Republican Army (IRA) and five from the Irish National Liberation Army (INLA) have provided the police with details. They have taken in hundreds of suspects for questioning. As a result about 250 have been charged with terrorist offenses.

In one case 41 people were arrested after a Republican in North Belfast provided information. Another Provisional returned from a religious conversion in the Netherlands and confessed to a murder for which his brother had been imprisoned. Around the same time a key member of the INLA in Belfast gave information which led to widespread arrests.

The informers come from paramilitary organizations on both sides. Recently a Loyalist who admitted his part in a murder was granted immunity and placed in police protective custody. His information led to the arrest of five men now charged with murder, bombings, and membership in an illegal organization.

The motives of the informers are complex. Some people have claimed that the police offer large sums of money, but this has been denied by the chief constable. He attributes the informant phenomenon to ''a new dimension in the terrorist scene.'' The police believe that in many cases the motives are simple.

One spokesman said: ''Conscience and a desire for a new life are the main considerations - not money.''

The conscience factor is difficult to estimate. The only clear case of this was the Provisional who returned from the Netherlands to confess to murder. Self-protection is thought to be a greater motive. If the police already have evidence about a leading terrorist, he may talk freely in return for immunity.

Without a doubt, this flow of information has shaken up the terrorist organizations. The Provisional wing of the IRA offered a two-week amnesty for informers earlier this year, but this was an offer some of its members felt they could refuse.

Despite the success of the people in presenting new evidence, there have been setbacks. Some informers change their minds and retract their statements. Recently 26 Loyalists were returned for trial on terrorist charges, but the Loyalist informer at the center of the case created a sensation in court when he refused to give more evidence, claiming that he had been forced by police to inform.

Police insist that there is no physical pressure involved. However the psychological pressure on a would-be informer in terms of family, old colleagues , and his ability to make a break with the past, are considerable.

The police don't know how long the flow of information will last, but they are pressing home their advantage while they can.