classical music Proms, Royal Albert Hall

Both Thomas Ades and Oliver Knussen have had compositions on show at the Proms this week. Two stupendously gifted musicians, neither gave much away. Ades, totally equipped for any task, is nearing the time when he will have to jump. His recent ...but all shall be well, which had its London premiere on Tuesday, behaves itself alarmingly well. Which other composer has made his orchestral debut with such restraint? The chain of events is quite complex but less cluttered than in Living Toys: easy enough to follow the progress of a quirkily droopy melodic line, less easy to tell whether to take its uneasy emotional overtones straight, or as an ironic pose.

Kent Nagano, conducting the Halle, placed Ades between Webern and Mahler - shades of Boulez programmes of 25 years ago. Nagano showed quick responses and a fine ear for subtle shades. But Mahler's Fifth Symphony went further, with an instinct for balancing tempo across a large span that made the whole experience build irresistibly from its melody-led opening to a sustained celebration of joy and innocence - an abundant, loving, vivid, cleverly judged performance.

Mahler was at the centre of Knussen's Thursday Prom with the BBC Symphony Orchestra, but a rum sort of Mahler. Todtenfeier, the unrevised first movement of his Resurrection Symphony, has a smaller but less fastidiously used orchestra, and includes a couple of unfamiliar passages, both first- rate (and presumably cut only to improve proportions). Overall, the impact is less momentous, especially when the whole metaphysical sequel isn't there. What did follow was a practical verson Britten made, with slightly reduced forces, of the second movement from Mahler's Third - as sweet as ever, but totally pointless when an orchestra that could play the real thing was on hand.

Both pieces were delivered with Knussen's usual fine ear, but without the nuances of pacing of two nights before. Knussen's own commission did not materialise. It's an old story, alas. Even the substitute work, Choral, begun in his teens, needed two years to complete. There's a great sound- image straight away, with brass growling like a Tibetan ritual, though the rest is effective but impersonal, or at least embryonic.

So to Hans Werner Henze's Symphony No 4. There is no middle way with this composer. Either he's all you think post-modern music should be, a worthy influence on the young; or he's lukewarm, harmonically impenetrable, and given to "lyricism" that never manages to sound like melody in the Mahlerian sense. This symphony has an alluring, lightly expectant start and a haunting episode of magic just before the final cry of pain. It's the steady flow of after-Berg moderato in between that is the problem. How many listeners knew which movement they were in without the programme- note's crib?