Okay, I have this old thin I printed in 2003. I've only recently read anything else hinting at what it contained:
http://goodcomics.comicbookresources.com/2011/02/13/comic-book-legends-revealed-300-part-3/ I'm going to retype the printout, skipping the first two paragraphs which regard Alan Moore's disenfranchisement with Marvel and some other stuff, rather than rehashing it.
"Chris Claremont, who was unaware of the political problems brewing, introduced Sir James Jaspers into Uncanny X-Men #200. His intention was to have the Alan Moore Captain Britain character infiltrate and eventually have a Jaspers Warp in this reality with the X-teams as the main thrust in the line-spanning story.
"Moore was unhappy about the Jaspers appearance and severed any chance of a reconciliation.
"[Stuff about not understanding the British copyright laws.] ... Marvel's lawyers allegedly recommended to Marvel that they avoid Moore's creations and story ideas [Moore actually didn't create a damn character from these stories, it seems]. Legalizing would cost Marvel a lot of money and wasted time so they upshot was they dumped the X-Men: Jaspers Warp idea. A friend of mine interviewed John Romita Jr. who said that he was 'really looking forward to playing with some of the cool characters that Moore and Alan Davis had created for the Captain Britain strip.' Amazingly, Claremont had intentions of not only introducing Jaspers from the UK Captain Britain stories, but also the Special Executive and the Fury (which at one point was firmly on the cards, as Alan Davis and Mike Collins had resurrected the Fury in Sid's Story and there was more of a haze around the character's ownership). [Sid's Story doesn't seem to be a way of bringing the Fury back, but who knows.]
"So, the Special Executive became the Technet, but what happened to the Fury? Romita also said there would be hints and subplots in other Marvel comics. I was out of the loop at the time, but perhaps others noticed odd things happening in their Marvel comics during 1986. [I don't think anything was going on...]
"I have also heard that Marvel insisted on a reference to the Jaspers Warp storyline in a post-Moore Captain Britain (I think this was Mike Collins' Sid's Story again) and there was also a mention of Jaspers Warp in an early issue of Excalibur. [There were many references to the Jaspers Warp in Captain Britain, but I don't remember Jaspers getting any kind of mention throughout Excalibur.] Then Claremont became privy to all the politicking and immediately rewrote his impending blockbuster and subsequently what Romita had suggested might be the equivelent of a DC Crisis (hot on the heels of the real one) was laid to rest.
"Around 1990, I stumbled across a lot of stuff about Claremont and Marvel's plans. I was putting together a column called Hypotheticals: What might have happened in Alan Moore's Marvel Universe. From what I can remember, the Marvel Jaspers Warp storyline was to begin in X-Men #200.
"Jim Jasper was introduced as the typical English baddie. The only person who capable of stopping him, Charles Xavier, was exiled back to space because his cloned body was packing up. The issues went very much the way they were planned to for six months, but then changes were made. Originally, Nimrod -- the futuristic sentinel living as a Hispanic good bloke in the ghetto -- was to stumble upon the remains of an entity that entered our reality through a hole in the spacetime continuum. Nimrod was to accidentally merge with the Fury and become not only indestructible, but also very smart. "Doc Doom times a googolplex" was one of the lines I read. [Sounds like Chris Claremont hyperbole to me! Nimrod fused with Master Mold in the 240's of X-Men, which I think was probably the recycling of this idea.]
"From this point on, you'll see what did happen in between the cracks of what didn't: Romita was leaving, so Alan Davis was asked to do it. He declined because of the creative restrictions. [According to Alan Davis (via Modern Masters: "Chris Claremont phoned and asked me to do the X-Men. I said I couldn't because I had just agreed to do Batman & the Outsiders. He phoned a number of times after that asking me if I wanted to do X-Men, and I kept saying no. Part of the reason, aside from honoring my commitment, was that I was really intimidated about the prospect of working with Chris." So the assertation that he didn't like the creative restrictions appears to be false.] The Mutant Massacre was to have been committed solely by the Nimrod/Fury hybrid. He would eventualy be stopped by Kitty phasing through him and disrupting his circuits. However, Kitty, Nightcrawler, Colossus and new character Longshot, were to have been relocated to Muir Isle for medical attention and to work with Captain Britain. Kitty was to be critically injured, as was Nightcrawler. [The link at the top indicates that phasing through the Nimrod/Fury amalgam would have caused her injuries. I assume this would put her in permanent phase, as happened in the Mutant Massacre we saw. It makes more sense than her getting hit with one of Harpoon's energy harpoons while phased.] Colossus was sent as protection and as a perfect foil for Captain Britain, who Kitty would develop a crush on. [Nightcrawler gets a thing for Meggan and Kitty gets a thing for Longshot, but Kitty never has a crush on Captain Britain in any printed stories.] Mutants, good, bad or indifferent, would begin to flock to Xavier's and with Phoenix II conveniently out of the way and Kitty and Braddock in Scotland, there were no members to see the parallels between Days of Future Past or with the Jaspers Warp.
"America would be in the thralls of mutant hysteria and Magneto -- now in charge of the X-Men -- would have to make some decisions that would affect the status quo. Allegiances would be formed with villains and new players, including Mister Sinister and others, would become prominent mutants through their covert ways.
"The UN would decree mutants a menace and Jaspers would meet Nimrod and susequently become aware he too was a mutant. [This occurs with the Master Mold/Nimrod amalgam, as well.] Unlike the Jaspers Warp, these two would become allies, or at least that is what Jaspers would believe. With reality falling apart and Nimrod culling mutants, Forge would be drawn into battle and what happened in the Fall of the Mutants story is essentially what was written, with the exception of the big fight scene and the denouement. Instead of being impervious to detection, the mutants who ventured into the Seige Perilous would return, with the warps they had undergone (some of this was used in Inferno, too).
"X-Men was going to be a darker comic and Excalibur the lighter side. X-Factor and New Mutants would pick up the pieces and rebuild mutant/human relations. And so now you know! (Whew!)"
Okay, this thing is quite mysterious. Going by what's written within, the story would have followed the battle with Nimrod and the Hellfire Club in Central Park that occured in X-Men #209. Rachel goes off to Mojoworld and Nimrod teleports away, critically injured. The Mutant Massacre happens just two issues later. Such a crossover would have been exhausting so soon after Secret Wars II just having ended its 9-issue run. We don't see Nimrod for quite some time, until he fuses with Master Mold in #246, so I guess he was kind of lost in the confusion of a major rewrite. Colossus and Longshot end up with the X-Men instead of with Excalibur, which ends up not having anything to do with Muir Isle. I'm not sure what was intended with Phoenix, but there was a Phoenix limited series that was started and never finished. A few pages can be found on the internet, featuring Power Pack at a movie. I get the feeling it would have contradicted what came after. As a matter of fact, it's never really said what happened to her on Mojoworld, except that her memories became confused and she fought Mojo. No mention of Psylocke in the above story summary either, so I wonder what her part was. Another interesting thing to consider is that -- as I've already said -- dead characters like Jim Jaspers and the Fury can exist in X-Men because Captain Britain was considered a seperate universe at the end, allowing them to use mainstream Marvel characters without confusion. This kind of contradicts the mandates to use the Fury and Jaspers in later Captain Britain stories, though...
This is kind of the crux of a change in X-Men. Things go off in strange directions and shakeups of the status quo become common. The next issue of X-Men I cover will be #201, the last time Cyclops and Madelyne Pryor exist as a couple, so X-Factor is right around the corner. Unfortunately, X-Men becomes a bit of a mess, more and more, in part because of the sudden cancelling of this storyline, I presume, plus the shoehorning of X-Factor into the mix. They are still good, but characters are lost in the shuffle and it becomes a bit directionless, losing its original intent. Perhaps X-Men #201 can be considered the end of the best period of Chris Claremont's X-Men, which isn't to say that there aren't lots of terrific stories afterwards.
Anyways, that's why I felt the need to go over Captain Britain in such detail (aside from the upcoming appearance in New Mutants of Psylocke/Betsy). Back to our regular dissections of issues next!