My experience has been different. Two years ago I arrived at Heathrow at 5:15 am for a 7:25 am intra-EU flight. I barely made that flight, and then only because it left late. There was nothing special going on that I knew about to delay things, and I didn't have any personal delays like being given a non-routine search at security or having trouble at the gate with my reservation. This was a smooth journey through LHR, and it took well over two hours for the ordinary, routine business of getting from the front door of the terminal to the plane! Afterwards, I tried to count up the number of different lines I had had to stand in; I think it was nine, but I may have forgotten some. That was when I decided that in the future I would never fly to or through LHR again, even if it meant not making the trip. (That wasn't the only reason, but added to all the other horrors of Heathrow, I decided that was it.)