Originally Posted by
orbitmic
As others have said, the last airline will always be the passenger's point of contact.
The question of responsibility is different, and BA will liaise with QR to ascribe responsibilities.
Finally, again, people should note that when you get an airline to through check a bag on successive itineraries, you should always approach an agent at the transfer counter of airport where your second itinerary starts to ask them to scan your luggage tag receipt, otherwise your luggage will almost never arrive with you. That is because even though the bag has technically been through checked, the system of the second airline does not know to expect the bag on your flight.
I agree that it will be BA that will probably reunite the bag with the passenger as the last carrier to have handled the bag, but surely QR are responsible (which is what the OP asked) They took responsibility for the bag at check in, and it is their tag on the bag. If the OP has to claim for missing or damaged ppbaggage that surely would be a claim to QR (and QR would be responsible for the claim and either take the claim on the chin, or attempt to claim those costs from BA)...
I am genuinely interested in understanding the right answer. But also hope the OP is reunited with their bags. For BA to turn around and say QR should not have checked through was just plain wrong.