Bill Drummond and Jimmy Cauty, who produced records under a variety of names, loved arranging situationist-inspired artistic events. They fired machine gun blanks from the stage while performing at the BRIT Awards in 1992, and later dumped a dead sheep at the entrance to an aftershow party.
Cryptic advertisements in the music press, books deconstructing the music industry and grand sloganeering were among other traits not regularly associated with groups who appeared on Top of the Pops.
It could be argued no other band is today recalled more for their statements than their music.
But the KLF’s most infamous - or celebrated, depending on your viewpoint - act took place in a remote boathouse on the Isle of Jura in the Inner Hebrides, a location far removed from the London-centric music scene, on August 23, 1994.
In the early hours of the morning, Drummond and Cauty were filmed methodically burning £1 million in cash - the bulk of the money they earned from record sales.
It was an extreme action that has provoked intense debate ever since.
Newspaper reports from the time could scarcely believe anyone would do such a thing - yet footage exists of the duo carefully placing handfuls of £50 notes into a fire.
But why did they do it?
Drummond was always more performance artist than pop star.
The son of a Church of Scotland minister, he was raised in Newton Stewart before moving to Corby, Nottinghamshire, with his family aged 11.
He trained in visual art and was involved with the Everyman Theatre in Liverpool by 1975. It was while living in the city he started a record label, later working with cult bands such as The Teardrop Explodes and Echo and the Bunnymen.
By the late 1980s Drummond was releasing records of his own. He teamed up with Cauty in 1987 to release a hip-hop record under the name of The Justified Ancients of Mu Mu. Despite several copyright issues and accusations of plagiarism, the album was a commercial success.
The duo scored a No 1 hit the following year with Doctorin’ the Tardis, a novelty hit attributed to The Timelords.
Further chart success followed when Drummond and Cauty rebranded themselves as the KLF.
As a dance music craze swept across the UK, the duo’s brand of ‘stadium house’ proved chart gold.
In 1991, the KLF were the biggest selling singles act in the world - an achievement that led to their invitation to the BRIT Awards and their infamous ‘machine gun’ performance.
As the band left the stage that night, it was announced over the PA that KLF had retired from the music industry.
A few months later, the duo issued another provocative statement - all of their singles and albums would be deleted and removed from public sale.
One music magazine declared the move as “the last grand gesture, the most heroic act of public self destruction in the history of pop”.
Drummond and Cauty then launched the K Foundation, with the aim of using their KLF profits to support struggling artists.
They soon decided the cash could be used to make a much bolder artistic statement.
In August 1994, Drummond, Cauty, long-term collaborator Alan ‘Gimbo’ Goodrick and journalist Jim Reid landed at Islay airport and took a ferry across to Jura.
Reid, the only independent witness to the burning, described the subsequent events in a report for The Observer the following month.
“The K Foundation have no particular regard for their financial security, but their relationship to that million is more complex,” he wrote.
“Cauty and Drummond tend to dismiss their past work. The million may have come from a critically-acclaimed music career, but to them by now much of it seemed like a failure. Perhaps burning the money is a purgative.
“The fireplace is a rough affair. Occasional fifties get wedged in crevices above the fire before they eventually fall down to be destroyed. Cauty is poking at the fire with a stick, moving the bigger bundles into the heat. Whole blocks of 50 grand remain resolutely unburnt: singed, charred, but perfectly legal. We have a bottle of whisky with us and it is passed round as if nothing could be more natural than burning £1 million on a remote Scottish island in the middle of the night. This is the truly shocking thing about the evening. It almost seems inevitable.”
Asked in 2004 if he regretted the stunt, Drummond told the BBC: “Of course I regret it - who wouldn’t!”
“My children especially regret it, but I don’t regret it all the time.
“I remember once, one of my children came home from school and said ‘somebody told me in the playground that you once burned a hundred quid - is it true?’
“I said, ‘I wish that was true!’
“A long time ago, we realised that everybody wanted us to have the smart answer, and we felt we owed it to people, especially our families, to have this.
“After a while, we realised that whatever answer we came up with would not be good enough.
“It was more for other people to take from it whatever they wanted, whether it be ‘they obviously didn’t do it’ or ‘it’s a terrible thing’ or whatever. It’s for other people to explore.”