Irma Thomas, Barbican Theatre, London<br/>Chase &amp; Status, Roundhouse, London

Even when the band don't know the dots, this soul survivor reigns supreme

The word I must use more frequently than any other in this column is "still" and, for variation, assorted declensions of the verb "remain".

It's born of a kind-hearted desire to say something positive about the surviving musical powers, physical appearance or general charisma of stars making their umpteenth comeback, and it's also a faintly sad reflection upon the state of the live circuit in the 21st century, and its reliance upon venerable old names to keep the cash tills ringing.

If there's one singer who deserves all the "stills" and "remains" in the book, it's Irma Thomas. The legendary Louisiana singer – invariably billed as the Soul Queen Of New Orleans – was releasing records when John F Kennedy was merely the senator for Massachusetts, and – here it comes – she still has a voice that's clear as a bell in the top register, and earthy as an allotment down at the bottom end.

The teenage Thomas was discovered, according to rock'n'roll myth, as a singing waitress overheard by bandleader Tommy Ridgley. In a phenomenally productive early period, on iconic soul labels such as Minit, Imperial, Chess and Rounder, with such later-to-be-famous writer-producers as Allen Toussaint, Van McCoy and Randy Newman, she recorded a number of the sacred texts of Sixties soul. She may never have broken through into the mainstream consciousness like her contemporaries Aretha and Etta, but many of her classic tunes have been covered more successfully. The best-known, "Time Is On My Side", was originally a B-side and, despite The Rolling Stones' best efforts, Irma's is the definitive version. The same applies to "Ruler Of My Heart" (reworked by Otis Redding as "Pain In My Heart") and "Breakaway" (by, er, Tracey Ullman).

It's that stuff, at her first British show in 20 years, which dominates. "I don't mix my gospel with my rhythm and blues," she says, "so there won't be any hymns tonight." At 70, Irma Thomas – here comes the other word – remains a phenomenal performer. Sassy, flirtatious, funny, and honest about her own shortcomings. When she can't remember the title of her Grammy-winning album (2007's After The Rain), she admits "When you've been doing this for 51 years, you can't remember everything you've recorded".

To help, she has a book of laminated lyrics, thicker than an Argos catalogue, that covers her entire half-century's work. Amazingly, she actively encourages requests. Given that an Irma Thomas crowd is by definition a knowledgeable, nay trainspotterish audience who really know their obscure soul, this is asking for trouble. Someone shouts out "In Between Tears", and she flips through: "I don't know if I have it ... Oh yes, page one-nine-seven-one." Even her superb seven-piece band, who look like they might have appeared in Treme (and quite possibly did), don't know this one, and they stand around like spare parts while Irma takes a verse and chorus herself, a capella. Incredible.

She may have the dazzling smile, expensively-styled hair, wedding-cake dress and sparkling diamonds of a Vegas cabaret turn, but Irma is the real deal. When the band strike up the tinkling, pitter-patter intro to "It's Raining", the heartbreaking ballad made famous in this country by, of all people, Shakin Stevens, the whole world turns black-and-white and you're suddenly transported to a dive bar in the French Quarter circa '62, getting the shivers when the torch singer behind the microphone hits the line "I've got the blues so bad, I can hardly catch my breath ...." It reminds me why, whatever other musical paths I may wander, I will always at heart be a soul boy.

Time may not be on Irma Thomas's side any more, but she's taking it on head first and winning. Still.

It's fitting, somehow, that Chase & Status should be the artists playing the most jam-packed night of this year's iTunes Festival. Theirs, after all, is the kind of music you're most likely to encounter non-consensually on buses and trains via the leaky speakers of an inconsiderate fellow passenger's iPod. (Seriously, what's the deal with that? Why the mentality of demanding to be heard? Where has that come from? And why can't we shut down the manufacturers of deliberately poorly soundproofed headphones and thunderous motorbike exhausts?)

If Chase & Status can't be held personally responsible for the way in which their fans play their music, they can certainly be tried for crimes against grammar for calling their debut album More Than Alot (sic). All they needed to do was call the next one Could Of and they'd be every Grammar Nazi's worst nightmare.

The duo of Saul Milton (Chase) and Will Kennard (Status) are the foremost British dance act of recent years to step up to the stadium-filling, festival-headlining level of Nineties giants such as The Prodigy, Basement Jaxx and The Chemical Brothers. This was largely achieved through moving from their early drum and bass style to a more commercial sound, for example by shamelessly sampling the same Loleatta Holloway tune as Black Box's "Ride On Time".

Live onstage, Milton and Kennard loiter behind silver 'C' and 'S'-shaped consoles while MC Rage and Andy Gangadeen bellow orders like "I wanna see carnage!" and "Jump-jump jump". They turn the Roundhouse into a cauldron of smoke, primary-coloured lights, chest-rattling bass and hands-in-the-air raving.

They're joined by Delilah for "Time", by Plan B on the video screen, back in his hoody-wearing days, for "End Credits", and by Liam Bailey for "Blind Faith", who dedicates it to "our friend Amy, queen of this town".

Subtlety isn't on the Chase & Status agenda. The whole thing feels a bit like being bludgeoned. I quite liked it, actually. Just not alot.

Next Week:

Simon gets his Vintage on at the South Bank in London

Rock Choice

The Apple Cart Festival, a new addition to the calendar, takes over London's Victoria Park (Sun). The tasteful bill includes Saint Etienne, Tim Minchin, The Magic Numbers, Patrick Wolf, Kevin Rowland and Chilly Gonzales. Meanwhile, The Chemical Brothers, Kanye West and Rodrigo Y Gabriela headline The Big Chill at Eastnor Castle Deer Park (Thu to Sun).