Sleaford Mods are on a national tour: Manchester today, London and Brighton next weekend. They should not be missed. A particular kind of grievance is their business: the smirk of a manager exerting his negligible power over the men and, especially, the women who work under him; the EDL twats gloating when their union adopts the 'British jobs for British workers' rhetoric; the unbearable, skin-crawling cruelty and bullshit of bureaucracy; the way all that swallowed anger lays you low.

Nottingham is the high point of this tour, a couple of packed hometown shows, a reminder. The city's specific class antagonisms - born of lace working, mining and quarrying, of food and reform riots, of the coalition and enforced dispersal of workers' movements, and of the gradual gentrification and segregation of its working class communities - roll in over the doorstep with the crowd. Outside, Nottingham is at pains to emphasise the high points of its radical history. The council erects plaques and statues, funds walking tours and bus rides to sites of former industry. It's fascinating, but pretty genteel: slide shows, well-designed historical maps, local historians murmuring over the gravestones of prominent charitable industrialists in Bulwell and Basford. Inside, the response to exploitation and class betrayal is less polite.

The two shows, despite sharing the same lineup and set list, are very different. Saturday is a homecoming celebration, a friends and family show, including a busload of Andrew Fearn's mates from Newark. The crowd is mainly middle-aged people waving and shouting along proudly, cornering Fearn and Jason Williamson for photos, quoting Sillitoe at me when I ask why they think this music is important ("once a rebel, always a rebel: dole offices talk you to death, offices milk your wage packets and rob you to death," one woman shouts in my ear, drunkenly paraphrasing Saturday Night and Sunday Morning). She lives in Carrington, near the gobshite middle manager so mercilessly portrayed in 'Fizzy': "we get pissed and lob cat shit in his garden," she says, laughing so hard she has to hold on to my arm, "and his dog eats it."

Sunday sees a more standard Nottingham crowd, the mix of lads and art-school cardigan-wearers often skewered in Sleaford's earlier lyrics. My friends patiently explain the intricacies of the local music scene to me: the angular Gringo records-type bands, constantly trading members; the twee and indiepop kids, the music forums and email lists, the DIY culture of the city. The line up for these shows is somewhat less orthodox. Though Grey Hairs are a Gringo band full of Nottingham stalwarts, they lay charisma and a Penthousey bluster on thick over their chromatic guitar. Endless Grinning Skulls are a different proposition again, crustpunks folding Yob and Killing Joke references into the shudder and shred, dual vocals at the fore. White Finger's latest release, the excellently-named tape 18 Minutes Under Sneinton, is a riff-driven affair that only hints at the excitement of their live performance. My notes from the night read "knelt screaming at my feet, his exposed belly evokes tenderness," for fuck's sake.

Oh, but watching Sleaford Mods is intoxicating, though. Williamson's characteristic gestures, the hand splayed behind his arched back, the cat-like flick over his face, and his verbal tics ("BOW! BOW, BOW! TOW TOW TOW TOW BO BO... fucking let's go") punctuate a perfect set, matched by Fearn's raver's lope, the shake of his head over his tin. Both nights, I am surrounded by people bellowing lyrics back at the band. Though some see them as careless scatologists, here in context all that bile makes sense, even to an outsider who will never truly know what its industrial history means to the political fabric of this city. It's clear at least that, live as on record, the sharpest critiques are reserved for the world of work. Powerless in it, stigmatised out of it, fucked over by union leaders, shat on by bosses, destituted by the state, all the familiar humiliations are here. 'Fizzy', 'The Wage Don't Fit' and 'Jobseeker' are delivered in such rage that it would be painful were I not enveloped by the noise of others all around me yelling in recognition. Isolated, those moments sound like popular unrest, and I've dreamed of them that way since. I didn't know how much I ached to hear that sound, so necessary and so rarely heard.