RRO / Slatkin / Kennedy, Royal Festival Hall, London

Still a virtuoso in bovver boots

He's back. Briefly emerging from self-imposed exile in Poland (far from the madding concert promoters and record company executives), Nigel Kennedy – or "Kennedy" as he previously insisted on being called – reminded us once again why he's the most original, the most wilfully creative and conspicuously gifted violinist of his generation.

They might have tagged this rare London concert appearance "Not The Four Seasons" but the audience would still have been huge and hungry. This is the man who filled the Festival Hall with the Berg and Walton concertos (unheard of), who turned up for the former as Count Dracula with white face and carmine lips but still mesmerised us with his artistry.

Kennedy infuriates as much as he thrills, but he still connects music and audience in ways that must bewilder even the cynics.

And so his legions of fans were out in force for an all-Elgar programme, clapping each movement of Leonard Slatkin's well-seasoned and nobly drawn reading of the Second Symphony, but listening, really listening, as the diaphanous coda carried us deep into nostalgia for the glory days of this "Green and Pleasant Land".

That is the title the Royal Philharmonic Orchestra have given to their festival of "quintessentially English orchestral music", and I suppose Kennedy might be considered the by-product of quintessentially English eccentricity. At any rate, there he was after the interval, still the eternal monster-punk-raver with his bovver boots and spiky mohican hair, punching the air, spoiling for this Elgar gig.

The Elgar Concerto – arguably the biggest and most demanding of the romantic repertoire – is as much a signature piece for Kennedy as Vivaldi's The Four Seasons. It's a throw-back to his beginnings at the Yehudi Menuhin School, and in two recordings and countless live performances he has systematically sought to extricate himself from the Menuhin tradition (he recorded it with the composer when he was just 16) and find his own way. That Kennedy's two recordings are about as different from one another as this performance was from either of them tells you a great deal about that journey.

Standing with his back to the main body of the audience for the long orchestral introduction, Kennedy turned into his first entrance with uncommon assertiveness, the G-string smouldering as if we were joining him at the end, not the beginning, of the journey. There's perfect musical sense in that: it's the last thematic memory offered as the work comes full-circle in the long cadenza of the finale. But from this imperative start, Kennedy immediately drifted into reverie with an almost static account of the ensuing pages. The wistful second subject was similarly protracted and dreamy.

So already the contrast between action and repose was extreme. Kennedy really played on these contrasts, lending credence to the view that if Elgar had been born in Austria he'd have been called Mahler. His innate sense of the work's fantasy was as striking as ever, with the rhapsodic, improvisational nature of the solo writing really connecting with Kennedy's love of jazz. As a performance it felt so completely in-the-moment that the feverish ascents to the big tuttis seemed to threaten spontaneous combustion.

Occasionally the failure of one of Elgar's wilder flights to land in quite the way Kennedy intended would bring a quizzical raised an eyebrow from him. But some roughness around the edges is inevitable if you really dare in this piece. Kennedy really dared, eccentrically so at times.

But Slatkin and the orchestra totally entered into the spirit of his reading, turning the sparring into sport in parts of the finale. I don't know of many conductors who could have so skilfully accommodated Kennedy's waywardness. But the performance's heart was always in the right place, and the right place was, most of all, the remote B-flat major of the great slow movement.

At the end, Kennedy knocked fists with most of the first violins and played some Bach. "Back to basics," he said. "Where would we be without the German masters?" Nobody was arguing with that.