Poland's Catholic Church made its first formal apology yesterday for the collaboration of many priests with the feared communist secret police. The country's bishops made the apology after the archive housing the security service files claimed that one Polish priest in 10 had passed information to intelligence agents during Poland's five decades as a Soviet satellite.

Under communism, "a system that crushed consciences, some men of the church also breached the trust placed in them", they said after a meeting in Warsaw.

"We regret that and apologise, particularly to those who experienced harm and distress," the bishops added, while warning against "creating an atmosphere of sensationalism and accusations."

Polish media regularly carry stories of priestly collaboration with the communists, which threaten to tarnish the church's reputation as a bastion of resistance against Soviet hegemony in eastern Europe.

The Institute of National Remembrance, which looks after Poland's communist police archives, said all the country's priests were the subject of a security service file from the moment they entered a seminary.

The institute also claimed that between 10 and 15 per cent of priests became police agents, mostly after being blackmailed or intimidated or threatened with a ban on foreign travel.

Poland was stunned when, shortly after the death last April of Pope John Paul, the institute revealed that a Polish priest at the Vatican had spied on the pontiff.

Fr Konrad Hejmo, who for many years ran a hostel for Poles visiting Rome, admitted to regularly meeting a Pole living in Germany who was later revealed to be a communist agent.

The institute of remembrance said Fr Hejmo gave the man information about the church and John Paul in return for cash and other gifts, but the priest denied giving him any sensitive information, or ever knowing that he was an intelligence operative.

Stanislaw Dziwisz, archbishop of Krakow and the former personal secretary of John Paul, established a Remembrance and Truth commission last month to investigate priests who worked as police agents.

The creation of the commission is widely seen as an attempt by the church to rein in media speculation about its communist- era collaboration.

The conservative Law and Justice party promised a "moral revolution" when it was elected late last year; many Poles fear it will use the archives to purge former communists. Several of the party's sympathisers have just taken up key positions at the institute.

Historians there say most priests passed mostly harmless information to their "handlers", although some were less benign.

Historian Janusz Kotanski said: "Of course, there were those who reported in a permanent, perfidious manner, with great intensity of their will. That was very painful for the church.

"But I believe it is in the good interests of the church to disclose these names, because it will show that the vast majority of priests did not let themselves be broken."