Originally Posted by
GUWonder
There is no train involved in that. "Due to boarding pass conformance checks at T5 even when doing terminal transfers from another terminal via tarmac shuttle buses, it's not possible for incoming passengers at LHR to get to the T5 train to get to immigration that way". There are other ways to get to Terminal 5 immigration without dealing with the conformance check.
Hmm, you chose a rather strange/confusing way to express your point then, since the impression given was that it’s not possible to change terminals to do immigration at T5.