At the time it seemed more a giggle than a gig.

Just demobbed from the RAF in 1946 after serving all through World War II as an air crewman, Herbert Newby thought it might be a lark to look in on the Gilbert and Sullivan tryouts being held in his native Manchester. He had sung in the cathedral choir and was rather proud of his lively tenor voice.

So he tried out. And before he knew it, he had signed a contract with the D'Oyly Carte company to sing in the chorus.

Soon he was understudying the tenor stars. And then, in 1948, he was asked to do the principal tenor role in "The Mikado," Nanki Poo.

The next year he quit over a contract squabble, but he came back in 1950 as one of D'Oyly Carte's stalwarts: There is a major tenor role in every Gilbert and Sullivan opera.

In 1956 he moved onto the staff as assistant director, then became director of productions, and in 1971 he advanced to the administration as business manager. He's still with the company.

He even married into the firm: His wife was Cainwen Jones, a chorister from North Wales and they were married in New York in 1955. Some lark.

"I beat him into the company by three months," she said. "Oh, the D'Oyly Carte was a matrimonial agency in those days. At one point there were six couples onstage who were getting married."

They had settled into their suite at the Intrigue Hotel here with the ease of people who spend their whole lives on the road, more or less. They do have a place in the Hampstead area of London. She uses teabags now (she whispered from behind her hand), but she did not manage to borrow a teapot from a neighbor so it would at least seem like home.

Earnestly they conferred with each other, their ruddy British faces concentrated as they counted on plump fingers: This is their 10th American trip, and they have now spent more of their married life in this country than in England.

They spent most of last weekend with friends in Virginia, and every trip there are people to look up from here to California.

All right, what is it about Gilbert and Sullivan? What in the world is it that keeps this Victorian silliness cranking along generation after generation with its parodies of 19th-century figures, its stuffy admirals, is Oscar Wildes, its ruling-class generals who keep to the rear because they "find it less exciting?

"For one thing," observed Newby, jiggling his gin and tonic in its plastic glass with the air of a good sport roughing it in the jungle, "it's a perfect match of lyrics and music, like Rodgers and Hammerstein, if you like. But there's more to it than that. Gilbert wrote about real people, you see, real human types, sort of universal. The same types still exist and I suppose always will."

Thus, the study of celebrity in "Patience" applies just as nicely to modern pop stars as it did to Wilde and A. C. Swinburne. And the Lord High Executioner's little list of people who never would be missed ("all irritating laughs . . . all children who are up in dates and floor you with 'em flat . . . and people who eat peppermint andpuff it in your face . . . and the plane-roganist, I've got him on the list . . .") is as fresh and deadly today as ever.

Some amateur productions update and localize the references, but D'Oyly Carte sticks to the original script with very few exceptions, such as addresses which have become meaningless over the years and the cocasional slang term which has become socially unacceptable.

Newby is often asked about the different attitudes to G & S in different countries: why, for example, "Gondonliers' 'goes over with a dull thud in America while in Britain it ranks second only to "The Mikado."

"I think it's a matter of what you're looking for. Americans seem to enjoy the social satire, the ridicule of government and those old British types. But there's another level to it: the musical satire."

British audiences are brought up on musical satire, from Percy Grainger to Hoffnung. They delight in the proof of Italian opera contained in the music of "Gondoliers" and the bombast of "For He Is an Henglish Man" and the wicked jab at Handel's choral monuments in "Trial by Jury."

Another thing about "Gondoliers": The average singer in the company dosen't like it because it is too purely musical and lacks dramatic punch. As in the other late works, Sullivan, the composer, was trying to break free of the partnership and was taking the music more seriously.

The laughs come in different places in America, too, Newby noted.

"In 'Pirates of Penzance' someone sings, 'Hold, monsters!" and the American audience breaks up. Well, it seems that 'monster' has a funny connotation here, with the television shows and the Halloween masks, Curious."

It takes a special kind of singer-actor-dancer to handle Gilbert and Sullivan. The stars become typecast, as with Wagnerians.

"You can tell a natural G & S singer right off in an audition," said Mrs. Newby, who sang as chorister and understudy for 17 years, a record in its time. "Some of them go on to Covent Garden or the English National Opera, and one joined the Met. It's a good training ground for the young ones."

Most of the stars, however, seem to stick with G & S for life. Martyn Green, the master of the patter songs, stayed with the company more than 20 years and became for Americans the personification of the genre. Current stars John Reed and Kenneth Sanford have bettered even that record.

Now that the copyrights have expired and the royalties can on longer be counted on to sustain the D'Oyly Carte, what is the future of these master interprters of Gilbert and Sullivan?

Newby smiled wrily at the lemon slice beached on the bottom of his glass.

"We've come to the crunch," he said. "We're not subsidized by the government, you know. We shold be. This tour is being sponsored by Barclay's Bank. We're just hoping we'll be able to carry on. Next year we may go to Australia, which will be the first time in years because they alway insisted on our using Australian choruses and we wouldn't. We go all over English-speaking world and some other places too, like Copenhagen and Rome. There's so much continuity: Do you know, the pianist who trained us for the roles was the same one who played for Gilbert himself?"

Some day, perhaps, the British government will declare the D'Oyly Carte a national treaure, like the Japanese Noh drama. Until then they will simply bob and skip along, keeping an age alive for us.