Just to note that considering the large number of CCTV cameras which almost certainly covered the incident it is quite amazing that no video footage has surfaced of the discovery and initial fire response.
It would seem that Fleet Street HAS cleaned up its act.
Who needs Fleet St when you have UtuBe?
As for the closure issue, I wonder if people are drawing the wrong comparison with what might have happened at AMS, FRA, CDG etc.
No airport would want to operate with anything less than 100% fire cover, and as pointed out above, this is something you have or you don't, no discussion.
Airlines might be operating on slim fuel margins, but again, there should be enough for TOGA or divert to another nearby airport, of which there are many in very close proximity.
The issue is surely one of runway capacity. An hour of diverts from LHR is going to take far longer to get back to normal than a similar situation at almost any other comparable airport, because there are only two available runways. However, I don't think that makes much difference to the arguments about building a third, as that would no doubt be full up soon after opening anyway, and I assume that even in special circumstances like this, the runway isn't going to be long enough to land many heavies.