Originally Posted by
Chokkoubin
Sorry to pile in here but as a Brit who lives in Finland I'm pretty familiar with T3 - arriving and departing passengers definitely do not mix. This is the case at every Heathrow terminal, and indeed every UK airport.
If you wanted to connect on int-int flights at T3 you'd have to go through flight connections security before you were released back into airside departures, which is where all the lounges are.
EDIT: This is extremely not höpö-höpö but here's the step-by-step guide the LHR website gives for the AY-JL connection in your example:
the question is, how would the lounge receptionist, or the gate know if you didn't go through FCC if you already have a boarding pass. The policy is, that you may not enter a lounge before security, but how is this enforced when you have an inter-terminal connection. In T1 they had security booths with attendants that didn't allow anyone back to the departure lounge, but there aren't such guards in T3. Also, I don't see any physical barriers separating arriving passengers (following the signs) from departing passengers.
As the original question relates to passage to lounges, how does one arrive at arrivals or the FCC without walking past them? What the signs say, and weather you're allowed into a lounge are related but separate questions.
The airline I was affiliated with, had a lounge near the main intersection, just outside the departure lounge. It was indeed possible for the passengers to pop into the lounge after there arrival in T3, to be told to follow the signs to Flight Connections as the policy was not to allow passengers into the lounge before security. If the person is connecting onto a different airline, and has a boarding pass, it is beyond me how the lounge can know if the passengers went through security.