LONDON — In a cramped, down-at-the-heels rehearsal room, the composer Anna Meredith was frowning at her laptop. In front of her were an electronic keyboard, a sound mixer bristling with knobs, two drums and a toy xylophone. A clarinet on a stand stood on the floor next to an electronic drum pad. After a short pause, Ms. Meredith picked up the clarinet, grimaced and glanced across at her bandmates. “Now, if I could just remember what I’m meant to be doing on this one, that would be terrific,” she said.
It was just over a week before the launch gig for her second album, and Ms. Meredith could be forgiven a touch of stage fright. The last time she was preparing to debut a major work was summer 2018 for the Proms festival at the Royal Albert Hall. Her ensemble on that occasion included the combined forces of the BBC Symphony Orchestra, the BBC Proms Youth Ensemble and a large choir.
Today, however, things were a little more D.I.Y.: a tight-knit group of electric guitar, cello, tuba, drums and electronics. Not to mention the composer herself, responsible for all the instruments in front of her.
Musical history is full of pop stars who yearn to be taken seriously on the classical side of the aisle, but the traffic rarely runs the other way. Ms. Meredith is a rare exception.
One of the most established British composers of her generation, Ms. Meredith in recent years has been popping up in the most unexpected of places. A few weeks after that Proms debut, she released a recording of her “collaboration” with Vivaldi, a joyously irreverent response to “The Four Seasons” using a combination of electronics and live instruments. A few weeks later still, she was back onstage, touring boutique summer festivals with her band.
Her music defies the usual attempts at categorization. In the last decade, Ms. Meredith has written a concerto for beatboxer and orchestra, a “gigue” for dance mat and electronics, a piece for chamber group plus recorded M.R.I. scanner, and a body-percussion piece for an orchestra to perform without instruments (“HandsFree”).
Animated by exuberant, juddering cross-rhythms, vaulting easily from frenetic, Terry Riley-ish minimalism to tranquil introspection, Ms. Meredith’s compositions seem to contain whole worlds. As blaring brass fanfares à la Janaceck collide with surges of caffeinated power pop, you find yourself wondering where she will go next.
Ms. Meredith isn’t always sure herself. “Someone once compared me to a shark,” she said in an interview. “It’s true: I do really like to keep moving.”
The new album, entitled “Fibs,” is as skittishly inventive as anything Ms. Meredith has written. The opening track, “Sawbones,” builds from a manic tuba and electric guitar riff to a maddeningly catchy chorus that wouldn’t be out of place at a 1990s club night. There are quieter moments, too: In “Moonmoons,” a graceful, melodic cello line soars over cooing owl sounds and plucked strings.
“The thing about playing Anna’s music is that it’s constantly changing,” said Maddie Cutter, the cellist on “Moonmoons.” “One minute you have a lovely melody, the next you’re doing these wild percussive chromatic things. Then there are all the crazy time signatures. You have to be really clued-up.”
Born in 1978, Ms. Meredith grew up near Edinburgh. As a teenager, she took clarinet lessons and played in a youth orchestra, but had little sense that music was her thing. Her first formal composition, written in high school, was for electronic keyboard, and required that the performer keep their hands on the keys, hitting the buttons that changed the instrument’s sound with their nose. (“Maybe I should dig it out,” she said, laughing.) It wasn’t until studying music at the University of York, then specializing in composition at the Royal College of Music, that she realized her gifts might be in any way unusual.
Success came early. By her mid-20s, she was composer-in-residence with the BBC Scottish Symphony Orchestra; by 28, she had won a coveted commission to write a piece for the Last Night of the Proms, the biggest jamboree in Britain’s classical musical calendar, which is broadcast around the world by the BBC. The piece she wrote, “Froms,” performed simultaneously by five orchestras, was, like many things Ms. Meredith has composed since, swaggeringly ambitious.
“The composing me is pretty badass,” she said. “When I’m working on something big, I feel totally unfazed.”
Yet she often felt uncertain about whether she really belonged in the contemporary music establishment, she said. Pulling a face, Ms. Meredith described once spending months writing an orchestral piece on commission, and being utterly dispirited by its debut performance. “The players didn’t seem to care, the audience didn’t seem to care, no one looked like they of it were having a good time,” she said. “And the piece was only played once, there was no recording; that was its only chance.”
This wasn’t a criticism of the way the classical world operates, she insisted: “I know I’ve been enormously lucky to get those commissions. I just wanted to do something where I had more control.”
So she decided to think more like a pop artist, and focus on writing tracks for an EP rather than pieces for live performance, she said. She also decided to follow in the footsteps of composers like Steve Reich and Philip Glass, and build a permanent ensemble. Sam Wilson, a percussionist and vocalist joined the group; as did a guitarist, Jack Ross; a tuba player, Tom Kelly; and, later, Ms. Cutter.
The group’s first album, “Varmints,” was released in 2016 to a mixture of acclaim and faint bewilderment.
Ms. Meredith said that, while some critics seemed surprised by her change in direction, she was really only irked by suggestions that somehow she was selling out in attempting more commercial projects. “It’s ridiculous, that assumption,” she said. “For a start, there’s so much more infrastructure and support in contemporary classical music, at least in the U.K.”
Ms. Meredith isn’t alone in trying to change assumptions about where contemporary music should be heard, or how. Just as composers like Olafur Arnalds, Nils Frahm, Mica Levi, Nico Muhly and Max Richter have become fixtures at festivals in the United States and mainland Europe, Britain seems to be in the midst of a boom in so-called neoclassical music.
The niche label Erased Tapes, based in East London, has found unexpected success with recordings of mellow, stripped-back instrumental music — so much so that Decca has followed with its own “postclassical” label, Mercury KX.
The London composer Gabriel Prokofiev’s long-established “Nonclassical” live events — somewhere between club nights and contemporary music sessions — have been an important showcase for projects that sit between techno, electronica, D.J.-led dance music and video art.
“There’s a lot of experimentation right now,” said the radio host Elizabeth Alker, whose show “Unclassified” is devoted to new music that straddles contemporary, alternative, minimal and numerous other adjectives. It has been a surprise hit on BBC Radio 3, an unabashedly highbrow classical music station. “Performers are thinking much more about the live experience, and audiences seem genuinely curious,” Ms. Alker said. “I honestly think they don’t care which category something fits in — or doesn’t.”
Ms. Meredith also said she felt that the musical landscape around her was in flux; having once experienced a degree of anxiety about where to place herself, she no longer entirely cared. “At the moment, I think my biography says ‘composer, producer, performer,’ which I think is maybe a bit much,” she said, then raised her eyebrows. “How about just ‘musician’?”