Originally Posted by
gusg
She has both US and Irish passports. She entered the API using the US passport. Would there be any advantage to using the Irish passport for the API? Could she even do that flying out of Boston?
Originally Posted by
SWISSBOBBY
I would enter on the Irish Passport to the UK as it is an EU passport...
Originally Posted by
Oaxaca
My point was that with the introduction of automated gate access for US citizens, the passport used likely wouldn't matter (though entering and exiting the UK on the same passport would be advisable).
Whichever passport the airline puts on the API is irrelevant to which passport you use to enter the UK, especially for an Irish citizen.
If in possession of an Irish passport I would always use this over a US passport to enter the UK, as Irish citizens are not regarded as foreigners in the UK while US citizens could be refused entry. For this reason I imagine that US passports might possibly take marginally longer at e-gates and/or have a higher rate of sending the holder to the human officer.
There are no formal passport checks when leaving the UK, so "entering and exiting" on the same passport is not straightforward. Even if an Irish citizen uses a US passport to enter the UK, they will not be in the UK illegally if they "overstayed" the grant of leave in the US passport. This may cause issues if the US passport is subsequently used to enter the UK again, hence it would be advisable to use the Irish passport in all cases. Meanwhile, exit checks are a case of matching API on departing flights to entries, but on a flight to the US, a US citizen should have their US passport data in the API which may not match up with earlier entry on an Irish passport, although it is possible that UKBF will have identified that the two nationalities are held by the same person.