Angela Hewitt/Britten Sinfonia, Queen Elizabeth Hall

When the Arts Council axe fell last week, the Britten Sinfonia was one of the few musical clients to emerge significantly richer, in recognition of its ground-breaking work both abroad and in less culturally-favoured parts of Britain.

And the coda to its Southbank event this week was typical: after the concert, key members of this outstanding ensemble gave a free performance of some left-field works specially commissioned for the occasion.

The main event kicked off with Bach’s fifth keyboard concerto led by Angela Hewitt - resplendent in a scarlet ball-dress - from her Fazioli. The outer movements were brisk, businesslike, and brilliant, with the slow middle movement radiating such tender intimacy that it intensified the surrounding silence. Her commanding touch wove a wonderful spell over hushed pizzicato strings.

In Stravinsky’s Concerto in D for String Orchestra, violinist Thomas Gould was the director, and he too exuded the right kind of authority. This neo-classical work turns on contrasting textures – moments of cloying sweetness cut with itchy frenzy and stark angular outbursts. The predominantly female ensemble infused this with the suggestion – true to Stravinsky, and taken up by choreographers who have made dances for it - that the whole thing is basically a series of sly musical jokes.

The ‘Jeunehomme’ piano concerto is one of Mozart’s supreme instrumental masterpieces. Here too Hewitt was at the keyboard, and in the lead, but less successfully than with the Bach. At times one felt a conductor would have brought the piano-orchestra tension into higher relief, and in the magical slow movement her touch – so ideal for Bach – lacked the crystalline quality which a player like Murray Perahia would have deployed. Winding up with Dimtry Sitkovetsky’s string arrangement of Bach’s ‘Goldberg Variations’, the orchestra presented a lovely sequence of duets and antiphonal episodes, but the chief pleasure lay in Thomas Gould’s timelessly pure and focused tone.

Then it was party-time in the foyer: 13 brand-new Goldberg variations performed by Gould, saxophonist Andy Sheppard, pianist Huw Watkins, violist Clare Finnimore, and cellist Ben Chappell. Three were tedious, a few did little and went nowhere, but those by Matthew King, Dobrinka Tabakova, Charlie Piper, and Elspeth Brooke all took the Goldberg argument on to new and unexpected places.