One of Britain's top TV shows is having a rough time making it on American TV. The show is called ''Fame.'' Yes, the very same Fame (NBC, Thursdays, 8-9 p.m.) which is having such trouble here finding a large enough audience to assure it a place on the NBC schedule has scored a huge success on commercial TV in BBC-land, where it has been in and out of the No. 1 spot for the past year. English audiences have not only taken the ''Fame'' series to their hearts, they have also embraced two of the group's RCA record albums, and the ''Fame'' kids themselves when they performed in a special concert at Albert Hall this past winter.
Now, with a new season, a new record, and a taped version of their concert (''The Kids from 'Fame,' '' tonight, 8-9 p.m.), the kids from ''Fame'' are hoping that American audiences will soon start showering them with the same degree of love and attention they grew accustomed to in England.
I have previewed an early ''rough cut'' of the special, which preempts tonight's regular ''Fame'' segment. It is a charming outpouring of the constructive exuberance of the regular series without the ''encumbrance'' of a story line, which sometimes slows down the energy-level of the series. And the lack of a story line doesn't matter, because the kids from ''Fame'' have already established their high-energy, high-morality characterizations and audiences know ''where their heads and hearts are at.''
I imagine that the producers added George Burns as narrator to make the show more palatable to adults - but it was unnecessary because the vigor and vitality of the kids are enough to charm anyone. They go through many of the original songs and dances they have performed in past episodes. If I have one complaint, it is that some of the dance numbers are a bit too slick, sensual, and sophisticated for the supposed age-level of the actors. The routines are more suited, perhaps, for the stages of Las Vegas than the hallway of a high school of performing arts.
''Fame,'' now in its second season on NBC, has been kept in the lineup mainly because NBC chief Grant Tinker believes it is a good, literate, quality show which he hopes will one day soon catch the attention of enough people to make it economically feasible.
Although I find the story lines often promise more in the way of insight than they manage to deliver, at least there is a consistent attempt to avoid sitcom cliches. About the only serious objections to the show have come from some educators who complain there is not enough of the pencils, sweat, and tears of high school classrooms and too much dancing in the corridors. However, one of the show's producers, William Blinn, insisted to me that ''Fame'' is not supposed to be a realistic show but a romantic fantasy, a 1980s musical comedy, not a sociological tract. Mr. Blinn worries that if ''Fame'' and some other NBC quality shows do not succeed, ''Grant Tinker may leave and some schlock-master may be brought in to do bad things. . . .''
I asked Tinker himself how committed he and NBC are to continuing with ''Fame.'' His straightforward response:
''I am very committed to the show, corporately and emotionally. We really think it is the kind of television we should be doing because it is unique and well executed. We really would like to keep it and hope we will be able to keep it, but I cannot say yes or no right now because it is a business judgment that we have not resolved yet. But it is definitely there for the balance of the season. The question then becomes, does it have a future. If it doesn't do in gross numbers what we would like it to do, it at least has good demographics (a young audience) in its favor.
''I dearly want it to stay, but I don't want to make empty promises.''
Mr. Tinker, who is often painfully honest (a refreshing quality in the broadcasting business) went on to say: ''If all of the good things we have been trying here fall to earth and lie there, I would really wonder if I should continue at NBC. I wouldn't want to preside over a schedule of successful junk.''
(Two new NBC shows, ''Bare Essence'' and ''The A Team'' might well fall into the ''junk'' category.)
It is apparent that we are approaching the demise of ''Fame'' unless it manages to capture a larger audience. With its tuned-in audiences hovering a little above 20 percent of those watching TV, ''Fame'' needs a few million more viewers to place it in a safe-for-another-season category.
Last week's ''Wizard of Oz'' episode and the ''Kids From 'Fame' '' special are indications that the series is engaging in ''stunting'' to attract attention quickly. If the show should fail and disappear from the NBC schedule, I predict that ''Fame'' will enter the record books as one of those golden shows which simply wasn't appreciated in its own time.
But there is still time to save ''Fame'' and, in the process, make certain that executives like Tinker continue their efforts to upgrade the quality of network programming. Try watching for a couple of Thursdays.