Copy editing
I lost count of "MAJOR" and "thwarted" (why does archaic English bubble up so?) and "foiled".
The best copy I found was this in the LA Times:
British police announced that they had arrested about 18 people in and around London early this morning on suspicion of attempting to blow up planes with devices hidden in hand luggage.
The Guardian has this:
... it is understood that officers made the arrests overnight, not because they feared an attack was likely to happen on Thursday but for other intelligence reasons which meant they had to act quickly.
I think "alleged" may no longer be a word.