Key routes list only seems to cover Europe? Looks like I missed out NY on the joined list - but still a few LGW to EWR to add to that.
If London just had one big airport, then I guess there wouldn't be so much confusion?
Sorry, meant to add - what would be the most popular city from the uk as a whole? Probably still DUB, judging by the FR routes from most cities, or AMS would be v. high too because of all the KLM feeder routes. Then NYC has a good collection of regional routes too - it must certainly trounce all other cities for long haul routes.