Interesting post peeteechase, I have recently retired from BA and have seen the locked door from both sides.
It was rather worrying to see from the club cabin (shorthaul aircraft) the way a "comfort break" was handled by the Captain (laid down procedure). As there was no screen (curtains etc) to obscure the exit from the flight deck and entry into the toilet it would have been the perfect time to join the queue for said toilet, as a couple of passengers did, knowing in the next couple of minutes the Captain would retrace his steps bak to the flight deck.
The captain, on leaving the toilet, went through the correct procedure to have the flight deck door opened from within, but with it open, had to squeeze past the loo queue to get to the door. A perfect oppertunity for others to enter!
I am told that other airlines close the curtain during flight and make an announcement that the forward toilet is not available. Seems very sensible to me, why is it not the case in BA?
Obviously on say the 747-400 there is no need to leave the "crew module" for a comfort break as all facilities are within. Such a shame that the powers that be decided against this "standard Boeing module" at the front of later longhaul aircraft aquisitions. It would have solved so many other problems as well ... perhaps I should contlinue in the "in charge" thread.