Nigel Kennedy clumps on stage in fluorescent yellow trainers and a donkey-jacket. Of course he does: that’s who he is, that’s what he does. If that bothers you, you’d already have seen enough to get steam jetting out your ears: the pretentious publicity, the daft programme notes (he’s making Vivaldi “relevant”), the eye-watering ticket prices (he’d never get away with those in the “classical ghetto”).

And then he turns to cellist Peter Adams, and launches into a performance of the Handel-Halvorsen Passacaglia so huge, fantastic and free that you find yourself straining not to burst into applause after each variation. He’s still got it: the gleaming, soulful tone, the lightning left hand, and a sincerity so powerful that he can hold an audience of 2000 rapt with virtuosity alone. You start to understand what it must have felt like to witness Paganini or Liszt playing live.

He’s combined a baroque orchestra with his regular jazz-folk line-up, and the evening began with homages to fiddle heroes like Isaac Stern and Stéphane Grappelli. Kennedy’s no composer. GCSE-level melodies (“it’s like Einaudi” commented my neighbour) alternated with freewheeling improvisations, Kennedy spinning through every trick in his technical armoury and hurling fragments of Dvorak, Beethoven and Deep Purple at his band members - who responded in kind. It’s not every day you see a bespectacled viola player physically leaping onto his chair for a solo.

And then, after some shambolic banter about the Villa, came Kennedy’s latest reinvention of Vivaldi - his “New Four Seasons”. Some movements he played straight, with a flamboyance and a fire that made you want to grab certain period-instrument practitioners by the shoulders and force them to listen. Others were simply trashed: the first movement of Autumn was reduced to the punchline of a musical joke.

But thrown in amongst it all, were moments – like the hushed, bluesy little interlude between Summer and Autumn – so beautiful, so heart-breakingly sincere, that it was like hearing pure music, straight from the source, pouring from the bow of this odd, awkward bloke with a ridiculous haircut. That’s who he is, that’s what he does.