"Inside Washington," a program of snappy political conversation hosted by political analyst Mark Shields, was a big hit on Capitol Hill, but that didn't save it from public television's ax. The weekly half-hour, unique in public affairs TV for its informality and Shields' down-to-earth approach, fell victim to the kind of bureaucracy on which it sometimes commented.

The Maryland Center for Public Television, which has produced "Inside Washington" since 1980, decided not to renew the program when its current season ended recently. Warren Park, the center's director of programming, said yesterday the show had failed to find an audience on the 77 stations that carried it. He also blamed its demise on a failure by the Corporation for Public Broadcasting, one of its potential funders, to perceive what the show was all about in the first place.

A CPB panel assigned to review the program reported back to the corporation that nobody needed another talking-head show from Washington, but Park said the Shields show was entirely different from other such programs. "It showed a side of the powerful people in Washington that other shows don't," Park said.

Thus did "Inside Washington" fall through a crack in the hugely cracked public television landscape.

Among the program's avid fans on the hill were Sen. Alan K. Simpson (R-Wyo.), Sen. Robert J. Dole (R-Kan.), Rep. Thomas S. Foley (D-Wash.) and Speaker of the House Thomas P. (Tip) O'Neill Jr. (D-Mass.).

Simpson said yesterday he was sorry to learn of the program's demise and that Shields was off the air. "I think he's great," Simpson said. "He brings a real breath of fresh air to that kind of activity. He's a dragon-slayer, and he has a spirited, light, pungent, wry kind of humor that attracts me, anyway."

O'Neill--who, like Simpson, had appeared on the program--said, "It was wonderful doing Mark's show. He's like the best sports columnist; he knows the game because he played it. He'll be missed a lot."

One of the shows Shields did, as it happens, was about the way politicians are addicted to sports metaphors. He also did programs on political commercials (with Washington media experts Doug Bailey and John Deardourff), political cartooning (with Herblock of The Washington Post), political speechwriters, and a program on Vietnam veterans that Simpson, who participated in it, called "pretty heavy stuff."

Shields said yesterday from his home that he was sorry the program was allowed to die, but that "I feel somewhat liberated. I don't have to make that trip to Owings Mills anymore." Owings Mills is where the Maryland Center's studios are located.

"We did some good stuff that I feel awfully good about," Shields said. "We were trying to show that politics is a human business. It's taken a lot of knocks, but it's important in the long run, and most of the really crucial things about the future--war, peace, the environment--will be determined by politics."

There was also a show or two Shields said he would just as soon forget. "We had two retired Secret Service agents on once," Shields said. "That one probably cost 20 IQ points off our viewership. They were nice guys, but they wouldn't tell you the time of day."

Ironically, the Maryland Center pulled the plug on "Inside Washington" just as Lawrence K. Grossman, president of the Public Broadcasting Service, was considering picking it up for national PBS distribution. During its last season, "Inside Washington" did go out over the PBS satellite, but not as part of the official PBS program "feed" to member stations.

"I thought Mark did a very good job," Grossman said yesterday. "What I saw of the program was very good. I thought it was a terrific idea to pick it up for our national program schedule." Grossman said, however, that it was "very tough" to get PBS stations throughout the country interested in another show about Washington.

Park said the program was attracting few viewers on stations that carried it, and that the CPB's failure to come up with underwriting was not the only reason it was canceled. "If the show had been doing well, we would have found the money," Park said. "It may have been popular among a small group in Washington but among many viewers throughout the country, apparently not. It was continuing to attract an audience below minimum standards in every market."

Park praised Shields as "a remarkable personality" and said, "We're sick about losing him. We love him here. He's just a hell of a guy, with a unique approach to political life. We're going to try to find some way to use him in the future."

Host Shields isn't the only one who won't miss the drive to Owings Mills. Simpson said, "I think one of the reasons Mark didn't always get the guests he wanted was the location of the studio. You had to get a safari together just to get out there. I said to Mark, 'I love you, but I'll be damned, that's too long a haul!' "

Shields conceded this had been a problem for guests. "People would promise to show up," he said, "and then on the day of the taping, they'd miraculously remember an appointment with their taxidermist, or that their favorite nephew was graduating from driving school. It's good to be off Route 395," Shields said--but not so good to be off the air.