One thing to keep in mind is that for British customers BAA and LHR may be close to a monopoly, but for others this is not the case. I fly through Europe to Eastern Europe, the Middle East, Africa and Asia 8-10 times a year. I like to take a stopover in Europe on the way as well. While sometimes my destination defines my airline (e.g. only LH flies to Eritrea), many times I have a choice. When Heathrow becomes too unpleasant, I can choose to switch to LH or AF. This affects BA (BAA's customer) and where I spend my stopover dollars as well. So it would behoove BA and CAA (that is, the British government) to put pressure on BAA to maintain a certain level of quality regarding the premises and the efficient movement of passengers.

With regards to Jenbel's comments, it may very well be that it is harder and more expensive to keep Heathrow safe than other European airports, and it may be that BAA does a better job of it than FRA and CDG. As a passenger though, I don't see this, given that, at this point, the probability of passenger injury or death in any of these airports has not reached the point of the actuality (CDG's collapse, aside).