SOE
Why do you say arriving in LHR T5 allows you to pass through security but not immigration ? I arrived BA from Hamburg and nearly missed my onward to GLA because flight connections DID take me through 2 dedicated immigration lines, neither of which was for EU passports and both of which were jammed by some non EU passport holder requiring 15 minutes of attention at the head of the line. UKBA ''service'' ?? Only made the GLA flight because it was half an hour late boarding. Such are the joys of LHR, even with BA straight through ticketing in T5.