I have found that sometimes flight connections from a domestic fligt can be a bit Heath Robinson-esque depending upon which gate your incomong (i.e. domestic flight) comes in on.

I seem to remember (I was connecting to t4), and all passengers had to walk up the jet bridge and turn right. Arriving passengers would then walk straight on, T5 connections would turn left and traverse up an escalator, and T1-T4 connections would have to perform a sort of U turn and wait in a melee (no room for a formal British queue) until the plane we had just got off from had emptied. Then the door to the jetbridge was closed, and they opened another door (that we would have gone through if we had walked up the jet bridge and turned left) and we were streamed through after showing our boarding passes for opur connections.

It was very frustrating, seemed to take forever and seemed thoroughly disorganised, but 'hard wired' into the building design. Very strange to me, maybe it is a 'once in a hundred flight' event, but the grumpy and rather dense BAA polizei's attitude did not help make it any better.