Scritti Politti, Tate Britain, London<br/> Betty Curse, Barfly, London

Just don't mention Avril

Having recently secretly made his tentative return to live performance after a 25 year-long lay-off, Green Gartside of Scritti Politti is going public, and playing an open-sided marquee in the front garden of the Tate Britain.

"Hello," he says, with a courteous smile, "and thank you for coming," and, if there are nerves, they're hidden behind his beard. In the shadow of winged bronze messenger-gods, this is one of the most sedate, bourgeois settings for a gig I've experienced (you can't buy cider but you can buy Pimm's). But Gartside has always been about defiant incongruity.

Never more so than when the 51-year-old white Welshman starts rapping lines like "we're gonna rock some shit" (on an afrobeat cover of a Jeru The Damaja track) or "put your motherfucking hands up" (from his own "Hands Up"). It's worth remembering that Gartside has a long history of such improbable cross-fertilisation (recording "She's a Woman" with Shabba Ranks and "Tinseltown to the Boogiedown" with Mos Def) and unexpected juxtaposition is his forte. Seeing him pulling rock faces, riffing hard, but singing considered words such as "correspondence and coherence", you instantly understand why it's Scritti, not Kajagoogoo or the Thompson Twins, say, who are playing shows like this, 20 years on.

One of the last of the great underground outsiders to stake a flag in the Eighties charts, Green Gartside refused to accept the artificial apartheid between highbrow and lowbrow, art and trash. Cupid And Psyche '85, Scritti's worldwide breakthrough album, brought a pristine Arif Mardin production, using then-fresh techniques of sampling and sequencing, to Russian doll-like, meta-metapop (songs about the language of pop).

After a difficult and intermittently drink-soaked two decades, Scritti are back with a new album, White Bread, Black Beer, which features all his finest trademarks. It's sounding sumptuous tonight, particularly "Boom Boom Bap", but as curfew approaches, we've only heard one classic ("The Sweetest Girl", made famous by Madness). "We can either play an old song badly," Green offers, "or a new song passably well". The answer is unanimous, and hearing "Wood Beez (Pray Like Aretha Franklin)" in the flesh makes me as happy as music has made me in 2006.

Betty Curse shouldn't be here. Rather than preaching to the converted in rock haunts like the Barfly, the goth-pop princess ought to be disrupting Party in the Park and the Smash Hits channel. That, no doubt, will come.

Betty Curse is the Alice Cooper-like alter-ego (interestingly, she says "we are Betty Curse" by way of introduction) of 19-year-old actress Megan Burns from Liverpool, who first tasted fame aged 14 in Danny Boyle's zombie flick 28 Days Later.

With her big, backcombed hair and black lemur eyes, she's the good-looking goth girl next door, and an increasingly confident and theatrical rock'n'roll front woman: a star waiting to happen. As a pop entity, she isn't entirely self-created - Island Records have a musical director on the case, and her songs were co-written with members of Eighties Matchbox - but her barbed, bitchy lyrics about self-harm ("Excuse All the Blood") and masturbation ("Rot in Heaven"), not to mention her lurid official biog ("a venom-pretty monster cloned by mad scientists from the spittle of Siouxsie Sioux, the tears of Christina Ricci and the shotgun brain mulch of Dead from Mayhem...") are clearly her own work.

For comparisons, forget Eighties Matchbox's demented rumble. If you strip away the ghoulish trappings, the Betty Curse sound is anthemic alt-rock/power-pop in the vein of The Runaways, Blondie, The Go-Go's and, dare I say it, Kelly Osbourne (just don't mention Avril Lavigne).

Dark and sweet, like black cherry bubble-gum.

s.price@independent.co.uk