I am still searching through my files to see what I may have on that "things will start in London" threat. I am afraid I am not too organized with these files. We have all tried to locate this before.
If I recall correctly, that threat was first written and as part of that request list with the 8 or so requests in late 2003; this letter had the number 223 at the end of it. It made another round slightly revised with the number 224 or so at the end of the letter in December of 2003 right before we started making those London flights return to London. It was signed by a group I think.
Then, it was then repeated by eom or an eom-wannabe after that.
The TM thread was from the week of July 10, 2004! It was because of the discussion about that threat that I started doing summaries. It is accessable from the first page of this thread in the link NWCTWX has provided. Apparently a source/letter was captured by the unspeakable site refering to the chain of events.