A good turn-out for a Thursday at the Sheldonian. Mozart’s Concerto No. 25, until relatively recently, was one of the least performed of Mozart’s most inspired works for piano. Maybe that’s because there are no crowd-pleasing heroics for the soloist in a piece that at times seems like a symphony with piano accompaniment, and a pretty grand one at that, rather than a concerto.

The opening movement almost seems half over before the pianist sneaks in, like someone quietly observing an animated conversation, and then making a few remarks before becoming an equal partner in the discussion. But once Angela Hewitt did join the musical exchange, her playing was pure poetry. She has a floating touch over the keyboard and her tone possessed a complete lack of tension, even in the loudest passages (which include clear echoes of the Marseilleise tune). And she shaped the individual phrases with such fluidity and apparent spontaneity that you could almost imagine the music being improvised by Mozart.

Maestro Papadopoulos proved to be a sympathetic collaborator and matched Ms Hewitt’s sense of being completely present with the music. I had thought the Philomusica’s timing for the double piano concerto with Maria Joao Peres the week before to be strangely hesitant, as if soloists and the band were under-rehearsed, but here they dovetailed like a synchronised gear set.

After the interval was Mahler’s Fourth Symphony. This symphony is influenced by the trend of the time to revive the classical style of Haydn and Mozart. This is arguably Mahler's sunniest symphony. Essentially it is a child's vision of heaven with, of course, some night terrors and a touch of bitterness, but overall still an upbeat and optimistic piece.

The orchestra had now swelled to 75, including four percussionists and a large brass section. Famously, the symphony begins innocently enough with the sound of sleigh bells and ends with a soprano (Julia Kogan, radiating joy though a little ill at ease with the notes at the bottom of the range) singing what in effect is a lullaby. Mr Papadopoulos went to town on the fortissimo passages in the first movement, no doubt wishing to make a high contrast with the many quiet passages that followed. Thus, the yearning tone of the adagio, with its clear foreshadowing of the 5th Symphony from a couple of years later, was followed and crushed by the tremendous fanfare at the movement's end.