People who work with Alabama 3 talk about them with pride, respect - and a certain amount of fear. Some call them "the last of a dying breed", others "the only real rock'n'roll group left". By the time I arrive in Salisbury, where they are playing as part of their current tour, the message is clear: some bands are all mouth and no trousers; Alabama 3 are a huge amount of trouser.
As far as jamming goes, the band have decided to up the ante and get me on to play in the gig. So, for one day, I became a member of Alabama 3. At 4.30pm the town hall in Salisbury is being crawled over by sound technicians and roadies. Segs, the bass player, pops down from the dressing room. "I'm off to get some carrots," he says. He does juice for the band before gigs - as far as healthy living goes, that will be it for the day.
Alabama 3 are more like the Alabama 7 to 11, but there's only a couple of them around for the soundcheck. Getting them all on stage requires a lot of agitated shepherding. The odds of getting Rob Spragg and Jake Black, the two frontmen, up there, I'm told, are on a par with raising the dead. But it happens, and the stage fills up with the resurrected, Rob behind an enormous pair of shades. We've decided to try a track called Gospel Train. "I've always wanted a trombone on that, Jake," says Rob. "It's fuckin' Christmas. Must have done something right this year."
Rob (aka Larry Love) delivers the tune in his decimated voice; Jake (aka Rev Dr D Wayne Love) evangelises over the top, both in deep south American accents. "That's fuckin' great," says Rob, and offers a hug. "Give it some of that New Orleans at the end. Come on for the encore too. Just go mental." "Aye, good," says Jake. "I heard a little bit of JJ Johnson there." Uh oh, he knows his trombonists. Rehearsal over.
Up in the dressing room, another journalist has come to do an interview. "You gonna do this one, Jake?" says Rob. He is now back to his Welsh accent: "You never get fuckin' Laurel and Hardy together, see Pascal?" He seems to have a hangover the size of Everest, but is enjoying its peak, like an expert mountaineer. Running down the back of his neck is a large, neat scar. He has recently been in hospital with a broken neck, after giving someone a piece of his mind at either a gig or a wake (stories vary). It's annoying him that he has to sit on a stool for the gig. "I wanted to come on in a wheelchair with two nurses in PVC outfits, and have two drips - one vodka, one tomato juice. But it freaked the band out. I think they were jealous."
The rest of the band are getting out their country shirts, funereal suits and wide-brimmed hats ready for the journey to Alabama. Jake is still in a grubby T-shirt having a big smoke. He may look all over the place, but talking to him leaves you feeling like you have never read a book, seen a film or listened to a CD in your life. In less than five minutes he covers: the unique cassette tape he had of John Coltrane playing Chim Chimney for over 90 minutes (someone trod on it); why Davis and Coltrane and Monk should be as revered as Mahler; the genius of Albert Ayler; his days as a journalist; why film students don't go for Bresson; the shirt that was made for him by the son of Celtic FC player Steve Chalmers. Oh, and my "metal gurus", which I work out means my shoes. Inexplicably, he's fascinated by them.
The manager pops up, looks around at the drink: "I thought this was going to be an alcohol-free tour?" "I think you mean free alcohol," comes the swift reply. Then Pix arrives. He's the guy who perplexes reviewers by just standing there on stage during gigs, looking like an enormous screw from an Alabama penitentiary. "Well, it was another night in south London or this," he says. "Put an Alabama shirt on if you're comin' on," says Jake.
Time to go on. Everyone is in place back stage, except for Jake, who is determined to finish his chat about authors who really push the boundaries of narrative structure. It's flattering, the kind of undiluted attention he gives a near-stranger, oblivious to the crowd waiting downstairs. Rob introduces me to Derek, his skull on a stick with two ivory horns: "Makes a great crack pipe." Seggs, meanwhile, is running through his collection of jokes about dyslexia. Dog help us.
Alabama 3 play a glorious, dirty show championing the world's underdogs. You could call it "country house" music. Tunes like Hello, I'm Johnny Cash and Woke Up This Morning (the Sopranos theme) are classics. I get chatting to a man backstage who is waiting to go on. "Oh, yeah, I know some people at the Guardian - my dad does too. The editor, in fact - and one of the crime reporters." He realises that I don't know who he is, and that the band are about to do a song about his dad. "He was one of the great train robbers, Bruce Reynolds."
"I found a young Big Issue seller with a trombone. Shall we give him a go?" asks Rob on stage. "Pascal the bone! From the Big Issue to big fuckin' Alabama. Look at the skinny little thing." I'm on. I put the lack of nerves down to the band: they are incredibly welcoming. I close my eyes, do my thing, and it is all over too soon.
Waiting for the encore, Rob pours himself a drink. Correction: he is relieving himself of a drink, which he plonks near the drinks table. "How much for a pint?" I ask. "Very expensive, this. A lot of good drugs in there." He looks at my shirt: "Far too happy, that. Next time we'll bring you on in a coffin."
"I'd take that horn off you if you couldn't play it. You know that?" says Jake. I take it as a great compliment. "The thing is, you're not a prick," says Rob. I take that as a compliment too.
· Alabama 3's Hear The Train A' Comin' DVD is out on One Little Indian on November 14. The band play Birkenhead Pacific tonight, then tour.