The reason LHR is getting a new terminal is because all the other terminals are handling several times more pax than they were designed to cope with, to the extent that aircraft are now delayed off stand simply because there's no space for their passengers in the terminals. T5 isn't planned to permit an increase in aircraft numbers, it's purpose is to allow an increase in pax numbers through the use of larger aircraft. I've never flown into ATL, but 4 parallel runways is two more than we have at LHR. I agree efficiency is the key to good runway utilisation, but our ATCOs cram as many flights into those two runways as is humanly possible. There simply isn't time or space to squeeze another aircraft in at peak times, as the permanent delays into Heathrow indicate. The assertion that there must be some slots available at peaks times is simply false. If there were, Branson would have them. We'd quite like an open skies agreement with the USA but not at any price. From this side of the pond this whole business looks like the usual US muscle tactics in negotiation.