Philharmonia Orchestra/ Mackerras, Royal Festival Hall, London <br></br> Ezio/London Handel Festival, Britten Theatre, London

The old man's having a ball and you're all invited

At nearly 80 years of age, Sir Charles Mackerras shows no signs of slowing down. A performance of Verdi's Un Ballo in Maschera is scheduled for his birthday (17 November). Meanwhile, his current cycle of Brahms' symphonies with the Philharmonia Orchestra reveals a musician of unlimited intellectual energy.

Unlike Kurt Masur's stately Beethoven Cycle with the London Philharmonic Orchestra, Mackerras's Brahms Cycle is no chauffeured tour of panoramic vistas. It is a breakneck stride through open country, led by an eccentric naturalist whose keenest wish is that you see, hear, smell, touch and taste each element of a complex terrain. On Tuesday night, his reading of the early Serenade No 2 conjured a profusion of greenery from an intimate ensemble of curling woodwind and horns, and reduced violas, cellos and basses. Phrases were elastic and impetuous, pianistically expressive, graced with subtle portamenti and vivid dynamic contrasts, and informed by Fritz Steinbach's meticulous records of performance practice in the 1870s.

However pure its musicological pedigree, Mackerras's iconoclastic approach is radical in the extreme when applied to a full-sized symphony orchestra. Rubato widens the stylistic gap between Brahms and Beethoven, and closes that between Brahms and Dvorak. It brightens the middle movements of the symphonies, lending their bucolic landscapes detail and colour. Without absolute unanimity of execution, though, that same rhythmic freedom unsettles the high-minded structure of the spacious outer movements. Had every member of the Philharmonia been on stage at the beginning of this programme, this might have been achieved here. But the connection established between Mackerras and the 27 musicians involved in the Serenade was of such an intensity that the players added in for Mozart's Piano Concerto in A (K488) and those who augmented them further for Brahms' Third Symphony were left looking like party-goers who had failed to notice the words "fancy" and "dress" on the invitation.

In the Mozart - ironically a model of how to work to great expressive effect within an unbroken tactus - any disconnection between the reserved upper strings and their mellower bedfellows was masked by pianist Paul Lewis's unaffected communication of the score. In the Third Symphony, however, there was a disturbing lack of definition from the violins and, oddly, the trumpets. Several of Mackerras's more daring tempi changes crashed and burned. The accelerating arpeggio figures of the first movement were propulsive to the point of overtaking the pulsing off-beats of the bass line, and the final beats of several bars were clipped. Still, those shifts in tempi that did come off were heroic in their impact. The cello melody of the first movement was thrilling, the expansive diminuendo across the following modulation as morbid as a humid summer sky in the moments before an electric storm. As in the Serenade, the chording of the woodwind was impeccable, while the playing of the lower strings and horns was among the most musical and shapely that I've had the pleasure of hearing.

For a conductor of his age, Mackerras's uncompromising adherence to Steinbach's model is remarkable. Given the vast difference in coherence between the Serenade and the Third Symphony, his elastic tempi and impulsive dynamics are clearly better suited to smaller forces. In the same situation, other conductors might favour pragmatism. But I admire Mackerras's idealism. In applying chamber-music affects to a symphony orchestra he is searching for a spontaneity that is near impossible to achieve in unison. That he found it here, albeit fleetingly, is a great tribute to the Philharmonia and handsome recompense for some unsettling transitions. Would I recommend the final programme of this extraordinary series? Unreservedly, yes.

As gut strings become a regular feature in the major music venues, Britain's early music festivals are in a state of flux. In Glyndebourne, the Orchestra of the Age of Enlightenment now takes precedence over the London Philharmonic in Mozart and Beethoven; annexing the hallowed pit of the Royal Opera House for Francisco Negrin's 2003 production of Handel's Orlando, and introducing modern audiences to a succession of Baroque operas in concert. So where does this leave the venerable London Handel Festival?

The number of Handel's operas and dramatic oratorios to be performed by mainstream companies has increased exponentially since 1977, the year of the first London Handel Festival. Nonetheless, it is unlikely that Ezio, Handel's 1732 opera of imperial intrigue and thwarted romance, would be heard outside a specialist festival or be sung by the highly promising young artists heard in the Britten Theatre last week. Niche marketing be damned. Aside from the dynamic musical direction of Laurence Cummings, LHF's strongest suit is in the fostering of new talent.

Though designer Roy Bell's elegant Classical ruins dominated the stage, the exceptional performances of Elizabeth Watts (Fulvia) and George Matheakakis (Varo) lifted William Relton's bland period costume production to another level. Accompanied sensitively by the orchestra - Neil McLaren's flute obbligati were particularly lovely - Watts and Matheakakis displayed a vocal maturity as yet beyond the reach of their sweet-voiced fellow cast-members. Watts's pliant, direct soprano has a shimmer and spin that recalls the (very) young Victoria de los Angeles, while Matheakakis is the most polished bass I have heard since Jonathan Lemalu trod the boards of the Britten Theatre. The score had some beautiful moments. (What Handel opera doesn't?) But the poignancy of Valentiniano's plight was diluted by Relton's reading of him as a pop-eyed parody of mad King George III.

a.picard@independent.co.uk