Alternative rock legends Radiohead on Tuesday released an 18-hour trove of private recordings from their 1997 album "OK Computer" after getting hacked by someone seeking a ransom of $150,000 for the music.
The genre-bending English musicians uploaded the 1.8-gigabyte collection of recording session outtakes and rare live performances on their radiohead.bandcamp.com website.
The songs can be accessed online for free.
The group is also selling downloads of an album of the 18 hacked MiniDiscs for £18 ($22.90, 20.20 euros) and donating the proceeds to the Extinction Rebellion environmental campaign group.
"We've been hacked," frontman Thom Yorke's wrote on the website.
"It’s not v interesting," he added. "As it’s out there it may as well be out there, until we all get bored and move on."
Guitarist Jonny Greenwood later tweeted a statement saying the hack occurred last week.
"Someone stole Thom's minidisk archive from around the time of OK Computer, and reportedly demanded $150,000 on threat of releasing it," Greenwood wrote.
"So instead of complaining -- much -- or ignoring it, we're releasing all 18 hours on Bandcamp in aid of Extinction Rebellion," he wrote.
News of the hack first emerged on a Radiohead discussion page of the Reddit website last week.
The user described how someone claiming to have the archive came in contact with a "well known leaker" and offered them previews of the tracks.
Awkward and challenging
The collection includes demo versions of "OK Computer" music and a few songs that never made the cut.
The critically-acclaimed album earned Radiohead their first Grammy and was followed by a world tour that gave them lasting international fame.
Its best selling single was "Karma Police" -- one of the most instantly-recognisable tunes of the 1990s and a staple of parties for the subsequent 20 years.
Radiohead were formed in 1985 and debuted their genre-bending hit single "Creep" in 1992. They were inducted into the Rock and Roll Hall of Fame in March.
They stopped using disposable cups on tour in 2008 and began filling their tour buses with biofuels.
Activists from Extinction Rebellion -- a fast-growing movement founded last year by British academics -- want world governments to slash greenhouse gas emissions to zero by 2025.
Their highly-disruptive but peaceful protests brought parts of central London to a standstill for 11 days in April and saw police make more than 1,000 arrests.