Originally Posted by
superscot
I would expect, admittedly as a UK passport holder, to be able to do plane door from AA TATL to BA lounge (including the T3-T5 transfer) in less than an hour (it was 40 minutes on Wednesday).
As a US citizen, I've had nearly as quick transits through LHR most times. The worst has been arriving at 11 pm; long and slow immigration lines. The BA lounges in T5 are really great, and make it much more tolerable.