Originally Posted by
BMarkus
Also the jetbridge (except some gates) are not designed to handle clean/unclean countries. When they would do it, transfers in LHR would so smooth. And any transfer between Terminals has to be consideres as clean (except public transport).
If government policy changed to allow it, in LHR it would just be a case of having "clean" arriving passengers sent into the departures area by the opposite route to which the passengers about to board that plane are about to take, just as is done at EDI or ABZ for domestic arrivals. It would have a knock-on effect to conformance at T5, however, and there would need to be a way for international -> CTA transfer passengers to be put through passport control.