Some might say 24 hours of non-stop cutting-edge music consisting mostly of electronic hums and swoops with weird writhing shapes projected onto the wall is a recipe for torment. Some might even be reminded of the joke about the man who enjoyed banging his head against the wall because it was so nice when he stopped.

But for the few hundred hardy souls at London’s Barbican, the London Contemporary Orchestra’s marathon performance – from 6pm Saturday until six o’clock yesterday evening – was a must-see event.

“You have to let go and get into the vibe,” one young audience member said to me as he left the auditorium to find some sustenance.

Had he slept? After all, it was 2pm on Sunday and he claimed to have been at the concert from the beginning. “Er …well I think I did a few times.” But, in general, he said, he had enjoyed every minute of the (up until then) nine sets he had listened to, ranging from John Cage’s avant-garde Eight (for eight wind and brass players) to Morton Feldman’s six-hour String Quartet No 2.

With so much music based on slowly shifting soundscapes, hadn’t he found it in any way boring? “That’s like focusing on the bricks that make the house, instead of standing back and looking at the house as a whole,” he replied.

The concert, which comprised 11 sets in all, ranging from one hour to Feldman’s six-hour string quartet, was something Robert Ames, co-artistic director of the LCO and curator of the event, had been trying to make happen for several years.

“I wanted to create a long-arching narrative in which people move from one musical world to another,” he said. “That takes time, so you have to give yourself to it for a long period.”

Ames isn’t the first to create this sort of long-form event. I’ve been to a number of six-hour and 12-hour concerts of cutting-edge new music in draughty halls, where at the end some weary joker calls out “Encore!” What made this event special was that the music was literally non-stop, which logistically was quite a challenge.

Seventy-five musicians came and went throughout the event, with the schedule structured to ensure no one was over-committed and everyone got a chance to sleep. It sounds gruelling, but cellist David Lale was in ecstasies. “What I love about this music is the way it plays tricks on your mind. The first quarter-hour of the piece I played went quite slowly, but the next 45 minutes went by in a blur.”

For my own taste the “immersive” electronic pieces hung heavy, but the gentle, ever-varying patterns of John Cage’s Eight were a delight, and it helped that I could slip out afterwards for a break. As Ames said as the concert drew to a close: “It’s not an endurance test. People can stay for an hour, or the whole 24 hours. If they go to sleep I don’t mind. There’s no right way to listen to this music.”