Originally Posted by
corporate-wage-slave
All Ireland inbound flights have to clear security before onward connections, for the time being, hence the arrangements at gate 23. There are moves afoot to change that, but it's probably 3 years off. If the travellers were coming from Belfast or any other domestic location arriving into T5 then there is no security check in LHR for a T5 departure.
Ah, didn't know that. Thanks.