honey lamb wrote:Ireland is better placed than LHR for Pre-immigration clearance because of the limited number of flights from EI, DL, UA, US and , given the number of mergers, any other American airline that flies in and out of my beloved country.
Which doesn't explain why immigration clearance is possible in Canada, where the flights and passenger numbers far exceed the UK - perhaps our airport infrastructure plus volume is the key

There's a plane at JFK, to fly you back from far away
all those dark and frantic transatlantic miles
all those dark and frantic transatlantic miles