THE CRITICS ROCK: As harmless as a cattle prod

You could tear yourself in half trying to catch all the troubled guitar troubadours currently storming our land. A few of them might get a kick out of that, so we turn first to something different - the mighty Ash, still too young by some way to be twisted.

Unless they make a silly mistake, which they're too knowing to do, Ash will soon be approaching world domination - though whether it's for longer than five minutes remains to be seen. Three years ago, they were pooling their dinner money to pay for demo sessions at home in Downpatrick and working out their obsessions with Thin Lizzy, the Stooges and Star Wars. They kept the riffs and intergalactic outlook, added walls of feedback and wah-wah guitar, dropped in exuberant lyrics about bee-stung girls in school skirts and turned into the Undertones-go-grunge. As a formula, it's close to unbeatable - and the responsibility of that and an album, 1977 (Infectious), that this week entered the charts at No 1, seemed to weigh on the threesome when they kicked off their tour at Bristol University on Wednesday, before a genuflecting student audience several years their senior.

Or maybe it's just the way they are. Rick McMurray hid behind his drumstack and Lennon shades. Bassist Mark Hamilton, a cross between Tigger and a greyhound on acid, tore around the stage and bounced off monitors with his gaze firmly fixed on the ceiling. And Tim Wheeler, the outfit's leader, stood in place, rang hell out of his guitar and often sang flat. Whether that was nerves or part of Ash's punk element, it played havoc with the first half of "Angel Interceptor", which nevertheless righted itself into a giddy gem, conjuring images of Captain Scarlet's Rhapsody, Symphony, Harmony and, above all, the girl next door. As the evening progressed, the band settled into a cool assurance - the mesh of noise mesmeric and almost brainlessly uplifting. Ash have been attacked as a "bouncy castle Nirvana", marrying doped Seattle thrash to a pain-free sensibility, but so what? They don't promise anything but fast, flash, throwaway pop. Wheeler's songs, which he delivers in a voice blending Jonathan Richman, Kurt Cobain and Pete Shelley, talk about drugs ("Goldfinger"), but also about martial- arts movies ("Kung Fu") and, ahem, astronomy ("Jack Names the Planets"). The limit of his angst is that he almost never gets the girl, but at 19 that's not the biggest deal and, according to the voluptuous "Oh Yeah", the memory of the crush makes it worthwhile. The set featured one cover - the Temptations' "Get Ready" - which was pretty wretched, though worth a shot. So no, Ash don't quite cut it live yet. But they'll probably have it cracked by next week.

"I think scorn is a pretty commonly felt emotion in relationships, and I'm happy to express it." So said Richard Thompson earlier this month, and at the Brighton Dome on Monday, the legendary folk-rock master of gloom was as good as his word. It's a confusing thing. From his stage manner, one would think Thompson a jovial sort. Flanked by Steven Berkoff- look-alike Danny Thompson on double bass and the versatile Pete Zorn on guitar, baritone sax, flute and rather suggestive eyebrows, he quipped his way through a two-hours-plus set full of repartee that Round the Horn wouldn't spurn. Eyes screwed up against the glare of the spotlights and grinning through his whiskers, Thompson looks like nothing so much as a self-satisfied guinea pig - and yet, no one can convey embittered disgust quite so well, or inflect an innocent word like "advice" with such splenetic ferocity. It may well be that Thompson's bleak take on the world has kept his fame at cult level ("Is he one of the Thompson Twins?" asked my cabbie); but though he's capable of knees-ups like the accordion polka "Don't Sit On My Jimmy Shand" and the Annie Ross-style scat "Hamlet", his saturnine disquisitions on romance shouldn't be missed.

The new album, you? me? us? (Capitol), deploys the usual vixenish women, psychopathic men and a handful of exes with stalk-on parts as ghosts, but it also reveals the coiled emotions beneath the mask, a deep regret and a longing for that old war to be over. Beside the vitriol of "Razor Dance", a husband-wife Lobster Quadrille complete with lethal pincers, sits the hoarsely desperate "Train Don't Leave" ("Hold that red light one more minute / 6.18's got my baby in it") and the unearthly waltz "She Cut Off Her Long Silken Hair". The set bustled between these and older songs, took in blues, jazzy breaks and sly, mandolin-embellished rockers given bite by Thompson's angular cadences. When he delivers it, you forget folk was ever mocked as bumpkin, finger-in-the-ear stuff. Harmless? As a cattle prod.

Steve Earle has a few loose demons, too. It's 10 years since his debut album, Guitar Town (MCA), woke Nashville from its New Country coma, but the compulsive personality that forged its renegade stories of wild times and prayers for redemption led next to a heroin-fuelled decline, a trail of broken marriages and a prison term. Earle's creative discrimination was already shot and his Texan economy blunted by pseudo-Springsteen bombast when he kept his date with gaol rehab. But he surfaced to produce two bruised albums, spare as Dustbowl blues. Unfortunately, in London this week, he proved that one addiction he is stuck with is the heavy-metal blitzkrieg that muddied his mid-period. Wheezing like a ruined Elvis, he could barely be heard at times over serial-killer guitars and fussy drumming. Only when he dismissed the band for a solo acoustic intermission did Earle approach the heart of his darkness, or confess true passion: on "South Nashville Blues", a Robert Johnson-style rag set in the black ghettos where he shot up for four years; the ragged heroin rhapsody "CCKMP" (Cocaine Cannot Kill My Pain); "Valentine's Day", a Tom Waits-bare devotional; and "Ellis Unit One", written for Tim Robbins's movie Dead Man Walking, and named for the Texas penitentiary wing with the busiest lethal-injection needles in the States.

Ash: Sheffield Octagon (0114 275 3300), tonight; then touring until 31 May.