Bob's full house

Good Bob. Bad Bob. They couldn't give a damn Bob. When you're a Dylan fan, you take the rough with the rough.

It was, incredibly, miraculously, just like the Sixties: crisp, audible lyrics sung with passion, tact and poise; clear political commitment; a concern by the singer to dwell within the songs and deliver them as if newly written; a deft manipulation of the overpowering noise that can be made using only a voice and six acoustic guitar strings. And then the support act (a Mr Elvis Costello) left the stage and Bob Dylan came on.

The deal with Dylan shows for so many years now has been as follows: when he's good, boy, is he good. But when he's bad, boy, does he suck. Not that this dismays his fans. On the contrary, Dylan's wild variance, his infinite unpredictability, is a major factor in their enjoyment. This is what draws the Dylan fans to Dylan rather than to more reliable live artists, such as Janet Jackson. The infrequent on-stage triumphs are hailed to the skies. Meanwhile the abject collapses, the nights when Bob is worse than rubbish, are greeted in the stalls with much sighing and shaking of heads but with no diminution of warmth. These are at once the most avid fans in the rock sphere, and the least easy to fool. They know that this is just the way it is with Bob.

So here come the fans again, in all their types, mixing it slightly uneasily in the standing-room-only section downstairs, or upstairs in the tumult of the un-numbered seating: the for-lifers; the admirers and freaks; the academics who like him because Professor Christopher Ricks does; and the Dylanologists and the Bob-spotters with their notebooks and biros, writing down the song titles as fast as they can recognise them (which isn't always that fast, given Dylan's tendency to meddle and mangle). At most other rock shows, people nudge each other and mutter when they've just spotted Dannii Minogue or Damon from Blur; here, they nudge and mutter when they've just spotted Bill Buford, the out-going editor of Granta magazine.

But here's a turn-up: no guitar! Bob has no guitar on! Honestly! Bob is not just unplugged - he's non-plugged. He's walked on to the stage and he's swiped the microphone out of the plastic clip at the tip of its silver stand and he's delivering the first couple of songs with the mike hand-held, as if he's Engelbert Humperdinck or Mark E Smith or someone. He's pacing stiffly to and fro in front of the drum-riser, he's holding the wire way out to his right and he's flapping his leg in a rock'n'roll manner. And during the second number, which is "I Want You", you're forced to confront the possibility that, any minute now, he's going to point, with a big showbiz forefinger, direct at someone in the audience and, with a glossy wink, sing, "I want... you!"

Actually, this doesn't happen. Instead he picks up an electric guitar and sets off deep into his back catalogue. No one was expecting a raft of new, unreleased material, cautiously harboured over the last decade and only now, on some fantastic whim, offered up to the Brixton lights. We get the firm favourites, though pushed to the limits of the recognisable by Bob's phrasing and, more importantly, his voice. (It disappeared down a long tube of metal guttering several years ago and it's been fighting to get out ever since.) He gave us "Tangled up in Blue". "Nargle ibid bleew," sang Bob. "Yay!" shouted the crowd. He gave us "Just Like a Woman". "Jez leg a lemon," sang Bob. "Wo!"shouted the crowd. And he gave us "All Along the Watchtower". "Hair muzzle summary udder ear," sang Bob. Total audience mayhem.

There was a slide-guitarist, Bucky Baxter, operating a number of lap- top instruments from a seat beside the drums. There was a guitarist, John Jackson, and a bassist, Tony Garnier, all slouched hats and pigeon toes. And there was a drummer, Winston Watson, with too many cymbals and a determination to hit them all at least once in every song. It was probably no coincidence that the show's unforeseeably fine moment came when the drummer had sloped off for a break, leaving the rest with acoustic instruments and Bob back on handheld mike, running over some of the material which we're probably going to hear on Dylan's forthcoming MTV Unplugged album. This included "Mr Tambourine Man": you might reasonably have thought you would never hear a version of this old chestnut that would make you think again about it - least of all one sung by Dylan. But bringing a hush down upon the room, he let his voice tumble softly through it and turned it into a glowing, twilit lullaby.

But immediately afterwards Dylan said, "We've got things to do and places to be," and the band promptly churned into a truly horrible version of "Maggie's Farm". So, there it was - at once good and crap. The man continues to confound.