When director Ryszard Bugajski completed a film called "The Interrogation" here several years ago, communist authorities were quick to let him know that he had gone too far. The harrowing portrayal of Stalinist-style police repression was quickly consigned to a censor's closet, and all mention of it was clipped from the state-controlled press.

Bugajski eventually emigrated to Canada, complaining that he had no possibility of working openly in his country. Since his departure, however, there has been a remarkable turn of events: "The Interrogation" has been viewed by people all over Poland and emerged as probably the most influential Polish film of the past year.

The reversal was not due to any change of heart by government officials. Rather, "The Interrogation" became the first movie to be spirited from its state lock-safe and released on videocassette by Poland's cultural underground. Thousands of copies have been circulating for 10 months, providing it a larger audience than many Polish films shown only in public theaters.

In the process, "The Interrogation" has opened a whole new sphere in Poland's crucial struggle over independent culture. In recent years, the ideals of the banned and largely dormant Solidarity independent union have been kept alive through an extensive underground of publishers and artists whose clandestine books and newspapers and church-based theaters, schools and art exhibitions have consistently undermined the government's control over information.

In many Eastern European countries, communist governments foresaw the political dangers of video technology and have limited the spread of recorders and tapes. But in Poland, authorities admit they have no control over the medium, allowing a boom in video viewing that appears to exceed that in any other Soviet Bloc country.

Although no official figures exist, video shop owners and the state-controlled press have estimated that there are already as many as 300,000 VCRs in private hands, and the number is steadily growing.

Opposition leaders now say they are prepared to capitalize on the government's failure to control the explosive spread of VCRs and tapes in this media-starved country.

"Video techniques will be the most important and most useful weapon in our hands this year, and within a few more years, we will work mostly in this area," an opposition leader said. "The possibilities for free expression in video are nearly unlimited in Poland."

The first entrepreneur of the video underground has been the Independent Publishing Office, or Nowa, the same group that founded Poland's now vast independent book publishing industry a decade ago. Since May, Nowa has produced and released three videocassettes of banned Polish movies and two tapes of independent news "magazines" about Polish events.

Within weeks, a Nowa activist said, the firm will distribute its most audacious offering to date: the banned play "Wieczernik," a politically charged religious allegory that was staged and filmed without official knowledge or consent.

"It's too late to help Bugajski," said the activist, who asked not to be named. "But we believe that we now have the possibility to be an outlet for a lot of Polish directors."

The cultural underground and its books, newspapers and classes follow a tradition of resistance in Poland that dates to its occupation by foreign powers in the 19th century. The new technology of video, however, gives artists and intellectuals a chance to reach a mass audience largely untouched in the past.

Although often unable to act openly, Solidarity groups still exist in factories around the country, and opposition leaders believe that videotapes could become a focus for their activity. Nowa is planning films that will address such practical questions as how citizens can respond to arrests or searches by police and how a home printing press can be manufactured from common materials.

"Videos provide a way for people to gather together, have discussions about what they see, and make decisions about their activity," the Nowa activist said. Unlike underground books and printing presses, moreover, VCRs are legal in Poland and those who watch them are unlikely to be raided or arrested by police.

Consumers now can buy a western-made VCR from state hard-currency shops for $310, and thousands line up each week to buy imported blank tapes.

For those who cannot afford such prices, private shops rent out VCRs and Roman Catholic churches around the country have installed their own machines. Many churches have also purchased their own video filming equipment.

More than a dozen private video rental shops licensed by the state offer about 1,500 different cassettes, most of them containing western movies pirated by shop owners and dubbed in Polish. There are also dozens of unlicensed shops. Customers can see a film like "Star Wars" for about $4, and pay $20 or more for under-the-counter pornographic films.

The extent of the video craze -- and the lack of official control -- was illustrated recently when the official youth magazine Sztandar Mlodych breathlessly reported that youths at an exclusive communist camp had been "besieging" a VCR to watch "hard-to-get films like 'Rambo' " -- a movie scorned by Polish and Soviet propaganda. "Total surrealism," the weekly Kultura said in dismay. "Activists from the ZSMP Union of Polish Socialist Youth are 'besieging' shows of violent anticommunist films. Does Sztandar Mlodych know why 'Rambo' is not shown in cinemas?"

In this kind of popular climate, Nowa's offerings of Polish films have been eagerly accepted. Viewers can buy a new cassette for about $47, or copy the film for about $6.

Most of the current studio-made titles were made for state studios during the heady days of Solidarity, then banned along with the union.

Nowa's managers say they hope to begin circulation of foreign-made films but so far they have not pirated the movies from commercial cassettes or western television, and instead are seeking permission from studios to use the films.

"We want to get official rights for political movies to be shown in Poland," the Nowa source said. "Above all, we want to show people real life and real political problems. That's something the official culture can't compete with."