Moving walkways failed, electronic message boards went blank and 17 of the terminal's 18 elevators died. Many passengers spent the night in the building after being handed form letters explaining that BA would be unable to provide hotel space but would be "happy to consider reimbursement of some of your out-of-pocket expenses."

Problems were exacerbated by the fact that terminal staff were unable to park, and some arrived for work as much as two hours late after finally making it through security. Confusing access-road signs also delayed departing passengers--fortunately, virtually all flights were leaving two hours late--and many complained of inept signage inside the terminal as well.

"Heathrow's showcase Terminal 5 . . . a national disgrace," said the London Daily Mail by day's end.

Blame seemed to be shared by British Airways and BAA, which owns the terminal (and is itself Spanish-owned). Many were irked that even though nothing else worked, the hundreds of fancy shops and restaurants in the terminal were doing a booming business. "The T5 shops are doing such a roaring trade," one angry blogger posted, "that the deafening sound of cash registers can be heard all the way to the City of London." BAA has always been adroit at turning its terminals into shopping malls, and some even say that airline delays and cancellations delight them, since grounded passengers are forced to shop.

BA began day 2, Friday the 28th, by canceling 20 percent of its Terminal 5 flights and warned that problems could persist into the weekend.

Saturday afternoon (the 29th) update: there are said to be somewhere between 15,000 and 20,000 pieces of luggage stored/abandoned/stockpiled/being vandalized in T5 as of now.  Huge numbers of BA flights continue to be canceled, and all press and TV cameras have been banned from T5.