The legendary unreleased LP, the darker, harder twin to the White Room LP by The KLF. It was referred to in interviews for ages, even before the White Room was released. Originally it was planned to be harder techno (like It's Grim Up North), then it was going to be heavy-metal techno (like America: What Time Is Love) and then it was going to be a thrash-metal collaboration with Extreme Noise Terror (like the TOTP version of 3am Eternal). It's unknown, how much of each incarnation was complete, before it was scrapped and recording was re-started.

Jimmy Cauty said of it in December '90: "The 'Black Room' album will all be this kind of electro turbo metal. It's not really industrial like, say, Throbbing Gristle, because it's coming from house and has an uplifting vibe about it. But it's so heavy it will just pin you to the floor."; while Bill Drummond said of it in March '91: "It's the compete yang to the yin of 'The White Room'. It'll be very very dense, very very hardcore. No sort of 'up' choruses or anthems. I think it's going to be techno-metal, I think that's gonna be the sound. Techno-metal. Which'll be, you know, a cross between Techno and Heavy Metal. Megadeth with drum machines."

One NME article noted that the "Black Room" was actually an ante-room to the recording studio they used in West London. It was originally scheduled for the end of '91, which was put back to March '92, and they were still recording in February '92 when they scrapped the sessions. Mark Stent, the engineer/producer for these sessions, thought the music was pure genius. "The most awesome track for me was one called "The Black Room and Terminator 10" which was like a very slow tempo thrash. It was mad. It was brilliant, absolutely brilliant, and it would have shown a lot of people up because it was as ballsy as hell. Guitars screaming all over the place, Bill doing his vocals and Dean (of ENT) doing his. There was such a raw power to it. It was so different from anything anyone else had ever heard. This was really heavy."

Furthermore, in Bad Wisdom, on page 206, Bill says  

"Z asks about the Black Room album that me and Jimmy as the Justified Ancients of Mu Mu started but were too afraid to complete. I tell him how, when I was standing in the twilight of the recording booth, the microphone in front of me, Jimmy's magnificent metal guitar riffs roaring in my headphones, a voice came out of me which I had never heard before, words flowed that I had never written and a precipice appeared before me. I crept forward and looked over the edge: the abyss. The Justified Ancients of Mu Mu's LP, The Black Room, was never finished.

But Z keeps talking and I'm warming to his persuasions. He feels that Jimmy and I are evading our responsibilities; we should return to our war-horse and complete the task. And yes, right now I believe Z may be right. But maybe Jimmy and I should wait until we are both over fifty before we record the sound of us as battle-scarred veterans of a hundred mercenary campaigns, when the music would not be drawn from our fading libidos but from the horror of life spent confronting that abyss - kinda like Milton backed up by Megadeth".