"There's no such thing as light music," said Stanford Robinson, not being very original. A genial man, a real pro, he was the BBC's acceptable face of classical music for the many who didn't really like it. For more than 40 years he was a staff conductor who conducted almost every kind of music in live broadcasts, without any rehearsal. But then, in the years before, during and immediately after the war, it was normal to put on major symphony concerts in this country with only one three-hour rehearsal. Last Friday's two-hour BBC Archive on Radio 3 celebrated Robbie's career, beginning with his own fragrant Valse Lente, and ending with Gilbert and Sullivan's Trial by Jury. Both are examples of "light music", and if it's not easy to define, there's no problem recognising it. What Stanford Robinson probably meant was that "light music" is not inferior (or failed) "serious", "heavy" or "classical" music. In his cabaret songs, Schoenberg - an exploratory genius if ever there were one - tried to write light music and failed. He couldn't smile; he could produce only a ghastly rictus. One of his pupils, Roberto Gerhard, of whose ballet Alegrias Stanford Robinson conducted the first performance in 1944, lived a potentially dangerous double life arranging light music and writing film and theatre music while also pushing the boat out in rugged, avant-garde compositions. It's no use denying that completely different frames of mind are required for writing music to please others and music to please yourself, and most composers will admit that it's not easy to reconcile them.

Matyas Seiber, like Gerhard, settled in England for political reasons, and also earned his living by writing for films. He had an abiding interest in jazz, and collaborated with John Dankworth on Improvisations for jazz band and orchestra, which Stanford Robinson conducted in an early "stereo" broadcast in 1964, one channel on VHF radio, the other on TV sound. The element of improvisation in this agreeably raunchy work probably wasn't any greater than in a period-conscious performance of a Mozart piano concerto, but that's still a considerable step beyond the usual "classical" approach to performing a totally definitive score.

And even in the performance of a totally definitive score, Stanford Robinson said that, in his day, the lack of rehearsal made for a lively spontaneity, though the Vienna Tonkunstler Orchestra sounded merely scrappy in Geoffrey Bush's performing version of the Scherzo from Schubert's "Unfinished" Symphony. Singers were different again, and Maggie Teyte and Heddle Nash enunciated an English translation of Massenet's Manon in the exquisite, clipped manner of BBC announcers 50 years ago. Nor did the singers in the musical comedy Big Business, recorded in 1934, sound anything less than Bright Young Things.

Heddle Nash appeared again in the series 100 Great Singers on Sunday afternoon, when the novelist Paul Bailey introduced some of his recordings. Echoing Sandy Burnett's point about Nash and Maggie Teyte in the Archive programme, Bailey said that the communication of words seemed much more important than it does to many singers today. That was certainly true when Nash sang English. Yet in the florid aria "Il mio tesoro" from Don Giovanni, he seemed to be thinking above all about a seamless line, as if to be noticed drawing breath were to betray a guilty secret.