Originally Posted by
Littlegirl
If you go down to B gates, it is hard to get back to A Gates without getting help from the security staff.
It's quite easy - when in T5B at Departures level, simply take the lift down to Level -4, which is the passenger walkway back to T5A Departures or to T5C Departures in the other direction.
Alternatively, take the lift to Level -2, which is the track transit level, and then go down the stairs behind the lift to Level -4, which is the passenger walkway.
I agree though, the tunnel is incredibly boring.