Originally Posted by
Often1
I would not make any assumptions about anything at this stage. How the UK chooses to physically configure LHR to handle traffic originating in the EU, transiting the UK and destined for the US, has any number of permutations.
Why would any one have to assume anything?
The airport is already set up to handle this, since UK is not a schengen country.
For non-UK connections, everybody already goes through security and there is no passport control regardless of origin.
For connections within UK or entering the UK, there is passport control and two lines: one line for EU/UK and another one for non-EU.
If anything, current EU pax would go to the old Non-EU lines where we Americans line up.
Nothing to reconfigure "physically"?