TP: Calm yourself. It was (I believe) a little banter from a Heathrow atco aimed at his Manchester colleagues based on their relative experience of 2-runway ops. If any of them want to get wound up about it then that's up to them, not you.
Also, I agree with 119.5. Some very experienced and impartial people from the CAA are going to determine what happened, so there is no need for any of us to speculate. Unfortunately, it seems that a few ill-informed spotters posting what they think they know both here and on airliners.net has resulted in the usual woeful press activity - the article I saw today in one tabloid rag had apportioned the blame to an atco (and had an interesting graphic showing aircraft departing 06L, with arrivals on 24L!). Is that remotely fair to the atco concerned? I note that the airlines involved were also willing to pass judgement. Shame on them.
It really makes me wonder. When every aviation-related article I read, without fail - broadsheet or tabloid, seems to have blatant inaccuracies or ridiculous sensationalism, what does that mean about the rest of the stuff that I rely on them to inform me about? Is it all cr*p?