As an opposition crowd gathered for mass May 1 at the St. Stanislaw Kostka church, several technicians of the Solidarity underground worked feverishly to construct a broadcasting system in a vacant apartment across the street.

After a long night's labor, the workers were dismayed to discover that secret police had set up a command post in a room above them. Still, they resolved to go ahead with their daring plan: Zbigniew Bujak, Poland's most wanted fugitive, was to address the church-going crowd live via a walkie-talkie hookup in defiance of the hundreds of assembled police.

At last, the broadcasting link seemed to have been completed, and the activists managed to leave the building without detection. But the risk proved worthless. The connection failed when Bujak began to speak, and neither police nor public heard any message May 1 from underground Solidarity.

One month later, following the capture of Bujak and two other leaders of the opposition underground, the failed stunt seemed representative of the decline suffered by a once-formidable conspiratorial organization. Hampered by decreasing public support for demonstrations and the difficulties of underground work, the Temporary Coordinating Commission, known as TKK, headed by Bujak, had been reduced to a largely symbolic status in Poland's political life.

Bujak's arrest Saturday after 4 1/2 years on the run seemed to spell the end for Solidarity of an adventurous, romantic era.

"Psychologically, it's a tragedy," said one former coordinating commission assistant, "but organizationally, it might not mean that much."

Bujak was the last well-known leader of Solidarity during its legal existence to remain a fugitive after the union was outlawed in December 1981. As such, he had become a symbol of Solidarity's stubborn survival through a clandestine network unprecedented in a communist state.

The organization he headed was a seven-member council formed in April 1982 to coordinate activity by opposition groups. It promoted the creation of clandestine printing and cultural organizations as part of what it called an "alternative society" in Poland and coordinated communications and the distribution of funds among them.

The coordinating commission's underground position allowed it to call for demonstrations, strikes and boycotts of official elections, all actions that Solidarity leaders living openly could not endorse publicly. It also organized occasional leaflet distributions and attention-grabbing stunts like pirate television and radio broadcasts.

The sudden strike by police forced some of the committee's workers who live above ground to go into hiding and could disrupt the flow of funds from Solidarity supporters, particularly in the West, union sources said.

At the same time, Bujak's organization had been largely superseded by the extensive, decentralized network it encouraged of opposition groups engaged in clandestine publishing, education and factory-level organization. In contrast to the fugitive council, this broader underground is run by thousands of people who live outwardly normal lives while working clandestinely part-time, Solidarity sources said.

The largely cultural aims and part-time character of these groups have proved better suited to Poland's enduring political stalemate than the action-oriented coordinating commission.

"This may be the time to dissolve the TKK, and give the direction back to some above-ground council, or Lech Walesa," the still-active former Solidarity chairman, an opposition publisher said.

Three opposition activists still live underground in Warsaw, and a statement from two remaining coordinating commission members made available to western reporters today said the group's work would continue. Opposition sources say, however, that fewer than a dozen Solidarity militants remain at large nationwide, and none commands the public respect that would be necessary to rebuild the coordinating commission as a political force.

For Solidarity's supporters, the most enduring legacy of the coordinating commission is likely to be its history as the latest in a long succession of Polish conspiratorial groups that have led daring opposition movements against repressive, foreign-backed governments.

Like the underground groups that fought czarist rule of Poland in the 19th century and the clandestine Polish Home Army that fought Nazi rule in World War II, Bujak's coordinating commission delighted many Poles simply by surviving against seemingly impossible odds. Police captured nine other leaders of the coordinating commission between mid-1982 and this year, but Bujak consistently eluded them.

According to sources close to the coordinating commission, Bujak disguised himself by gaining weight, growing a goatee and wearing glasses and an occasional wig.

Bujak and the two close associates also arrested Saturday, Ewa Kulik and Konrad Bielinski, operated for several years through an elaborate system of safe houses and apartments made available by Solidarity supporters.

Elaborate operations were staged so Bujak could meet his wife Waclawa. Once, a group of supporters transported Waclawa to a church in central Warsaw while a separate group brought a change of clothes. A sympathizer who participated said Bujak's wife entered the church, changed clothes, left by a different exit, and proceeded to a house outside Warsaw for a three-day family visit.

For opposition activists, such stories became part of a folklore that inspired dozens of others who never met Bujak and took only occasional risks.

"It really lifted our hearts," one underground publishing activist said wistfully last night. "It showed us that we could go on, despite martial law, despite the Reds."