Co-leader of Northern Sinfonia Kyra Humphreys took centre stage last night, as both leader and soloist, directing the players through a strangely mixed programme of Mozart and Shostakovich. If nothing else, this juxtaposition demonstrated the incredible versatility and range of this orchestra, because switching between pieces of such contrasting mood and style must have required quite a big mental gear-change.

The Mozart pieces in the programme were played with Northern Sinfonia’s usual delicacy and style, exemplified by the crispness and lightness of Humphreys’ ornaments in the solo parts. Every grace note was tucked in with absolute precision, like tiny little jewels. The violin solo was complemented by Juliette Bauser’s beautiful flute tone in the Adagio in E and by sparkling oboes in the Rondo in C which followed it.

The “Haffner” Serenade and the March in D which accompanied it were written for Siegmund Haffner, a Salzburg businessman and family friend of Mozart, for a garden party given on the eve of his sister Marie Elisabeth’s wedding – music for a hen-night, as the programme notes put it. The eight serenade movements were perfect party music; light, elegant and unobtrusive. The dance movements had a swing to them that harked back to French Baroque music and the brass interjections also suggested music of an earlier era.

The solo violin, flute and oboe sections all had their moments in the Haffner. Kyra Humphreys’ performance of the fourth movement (Rondo) had a lovely energy – this movement is almost like a miniature violin concerto, giving the soloist a chance to shine. I also enjoyed the solo oboe section in the gentle sixth movement, and some more shining flute playing in the third of the minuets.

In contrast to all this frivolity stood Barshai’s orchestration of Shostakovich’s String Quartet no. 10, known as the Chamber Symphony in A flat. The change of mood was set before the piece even started as we had a longer than usual pause between pieces whilst Kyra Humphreys changed out of her gorgeous electric-blue soloist’s frock into sombre black so that she could take her place back among the players.

Shostakovich’s chamber works are intense and personal; the string quartet was a private medium where he could reflect on the grim realities of life in Soviet Russia. His friend Rudolf Barshai arranged a number of them for chamber orchestra, and although the larger, richer string forces alleviate some of the bleakness in Shostakovich’s string quartet writing, they are still troubling, restless works, that demand close listening.

Northern Sinfonia’s performance was tense and exciting; the first movement ground on relentlessly, becoming more and more sinister, before exploding into the screaming chords of the agitated second movement. This was a masterly performance, tightly controlled, never too loud, and absolutely absorbing. The gentle third movement gives some respite, with a warm melody meandering along in long ambiguous phrases over unsettled harmonies, then a wonderfully nimble viola motif leads straight into the Allegretto final movement. The excellent acoustics of Hall One at The Sage Gateshead meant that the first violins could make their long, unrelenting pizzicato passage incredibly quiet, and the syncopated pizzicato passages that came later were immaculately timed.

Every section of the Northern Sinfonia strings were excellent, but the double basses have to be singled out for their moment of glory in the fourth movement – a wonderfully dexterous little solo passage, and they were deservedly picked out first by Kyra Humphreys for sectional applause.

Although the Mozart and the Shostakovich were both first-class performances, putting them together on the same programme simply did not work. The “Haffner” Serenade particularly, coming after the intensity of the Shostakovich, felt terribly banal, and I couldn’t help thinking that whilst it must have been lovely background music for a garden party, it wasn’t really a work that stands up to the scrutiny of a concert performance.