Gilbert and Sullivan worried about copyright more than most creative artists - understandably enough, since their copyrights were violated more often and more flagrantly than any others in the field of opera, sometimes with two or more pirate productions of one work competing in the same city with an "authorized" production.

The worry was not only financial (though that was a strong and a fully justified element); it was also artistic. In the hundred-odd years since they began to appear, these works have been produced with every kind of distortion imaginable, including jazz "Mikados" and one (in pre-Hitler Berlin) where Yum-Yum appeared naked.

Gilbert and Sullivan were concerned for their work's immortality. "It is a shameful thing that copyright should expire," said Gilbert. "It ought to be freehold like land."

To keep the copyrights active as long as possible, they were turned over to the D'Oyly Carte Company an organization that has a fair chance of outlasting the House of Lords, and the D'Oyly Carte Company preserved and protected the Gilbert and Sullivan tradition as carefully - some might say rigidly - as it could. Catastrophe was expected when the copyrihgts expired (Sullivan's music in 1950 and Gilbert's words in 1961), and there were indeed some oddities - a recording of "The Mikado" starring Groucho Marx, for example - but on the whole I would say that the results of the new freedom have been positive. The tradition is still preserved, but the watchdogs can no longer enforce their interpretatoion as the only one possible. Other companies (the New York City Opers, for example) have produced Gilbert and Sullivan with a quality comparable to that maintained at the sacred shrine and, in some ways, better.

The improvement is chiefly in the area of pure musicianship and most notably in the quality of the voices. The simple fact is that the D'Oyly Carte Company has trouble attracting and keeping firstclass voices; a singer who has the option of singing Verdi, Puccini, Purcell and/or Wagnerr is naturally reluctant to devote an entire career to such roles as Jack Point or Princess Ida, unless that singer is more interested in security and familiar routine thatn in adventure and new challenges.

A monument to the end of the Gilbert and Sullivan copyrights have just been released on Seraphim Records (a half-price subsidiary of Angel). Originally released not long after the Gilbert copyrights expired, these recordings of "The Gondoliers" SIB-6103, two records) and "The Pirates of Penzance" (SIB 6102, two records are musically the most satisfying Gilbert and Sullivan I have heard on records, precisely no doubt because the solo singers - partically a who's who of British voices - are not identified with the D'Oyly Carte Company.

Most of the singers - basses Owen Brannigan and James Milligan, baritone John Cameron, tenor Richard Lewis, contraltos Monica Sinclair and Marjorie Thomas, soprano Elsie Morison - appear on both sets, forming a sort of ad hoc repertory company that easily outpoints D'Oyly Carte in its overall quality.

Even more distinguished are some of the singers who appear in only one of the sets, such as Geraint Evans and Helen Watts in "Gondoliers," George Baker and Owen Brannigan in "Pirates." Baker, in particular, is a noted Gilbert and Sullivan specialise with a recording career that extended from 1917 to 1962, although he never joined the D'Oyly Carte Company.

The most notable musical contribution to these sets is that of Sir Malcolm Sargent, who did conduct frequently with D'Oyly Carte, beginning in the 1920s, but who received considerable criticism from conservatives because he took some liberties with the score - notably in speeding up some tempos. With the Pro Arte Orchestra and the Glyndebourne Festival Chorus, he gives the music exactly the right accent on these records - light, bright, brisk and delicately textured.

We may expect the more of Sargent's Gilbert and Sullivan performances from the early '60s will be reissued in this relatively inexpensive format. I await the splendid "Iolanthe" and "Trial by Jury" with particular eagerness. My old copies have earned a test.