I will concede the environment is generally not for the faint hearted - MrsNWI & I were once first into the lift in T5A, pressed the -4 button for the passageways, and no-one who followed us in selected the train level. Cue general confusion when the lift doors opened and we saw what must have looked to everyone else a very austere panorama, followed by complete disbelief that we were actually getting out to walk. Unless I knew the drill, I'm pretty sure I'd think I was somewhere I really shouldn't be - so the advice of the lounge staff if asked the question seems perfectly sensible to me.

We've also had people ask us why we weren't getting off at the train level, and when we explained coming down to the passageways with us. When we got there, half of them trusted us and walked [which probably got worse for them as we quickly disappeared out of sight], the other half had second thoughts and went back up again!

It really is best that not too many people know - the speed of getting through now is largely because, aside from the very occasional buggy and BA crew member, there's no-one down there to get in the way. The option will be much less attractive if suddenly it becomes a mainstream way of getting around.