Proms: ROYAL CONCERTGEBOUW / RICCARDO CHAILLY Royal Albert Hall, London

No other foreign orchestra has made as many appearances at the Proms as the Royal Concertgebouw, and with concerts last Tuesday and Wednesday under their chief conductor Riccardo Chailly, this magnificent body of players once more drew capacity audiences to the Albert Hall and made an electrifying impact. It was fitting that they had been invited to contribute to the season's complete Mahler symphony cycle: ever since the composer first conducted the orchestra some 90 years ago, a vital Mahler tradition has been sustained in Amsterdam, and with quite magnificent playing in the Lieder eines fahrenden Gesellen and the First Symphony, the Concertgebouw reconfirmed its absolute mastery of his style and unique vision.

To begin with, however, we heard a fascinating novelty in an orchestration by the Dutch composer Theo Verbey of Berg's early Piano Sonata. Aiming to clarify the complex polyphonic working behind the keyboard texture, Verbey employed an orchestral style based on the composer's Three Orchestral Pieces, and he did so with the utmost refinement. This could have been the work of Berg himself, and apart from handsomely realising his intention to focus details of thematic and contrapuntal working, Verbey has created a profoundly searching poetry with his range of expressionist colours.

The orchestra brought the delicate and often chamber music-like sonorities radiantly to life, and then served the exquisitely weighted accompaniments of Mahler's song-cycle with equal mastery. Baritone Wolfgang Holzmair characterised the composer's poignant regret over a lost love with heart- breaking intensity, and the uncanny psychological and atmospheric precision of the orchestral colouring was rendered to perfection. Two of these wonderful songs supply material for the First Symphony, and here, too, the orchestra and Chailly were perfectly attuned to the young Mahler's burning vision. Whether exuberantly striding, uncovering nature's mysteries or singing of love, the symphony revealed its deepest secrets.

The music-making proved just as masterly and persuasive in the French and Russian styles of the second programme. One of the highlights here was the dazzling playing of pianist Jean-Yves Thibaudet, and after the orchestra's highly charged performance of Debussy's La Mer, he gave a miraculously judged interpretation of Ravel's Piano Concerto in G.

The finely honed surfaces of Ravel's orchestral style are sometimes in danger of concealing the touching poetry beneath, especially when, as in the present work, a range of brittle 1920s-ish mannerisms are also employed to distance the listener still further. But it was Thibaudet's great achievement that he articulated the work's scintillating surface with consummate mastery, yet remained in touch with the deeper substrata of feeling. The orchestra supported him with wit and delicacy and the performance drew a deserved ovation.

Thibaudet's virtuosity and poetic vision were also superbly geared to the flashing colours and whirring textures of Messiaen's Oiseaux exotiques, which received a stunning performance, and this memorable Prom closed with Chailly and an enlarged orchestra triumphant in Stravinsky's 1945 suite from The Firebird.