When your flight is officially designated as cancelled on the system, you can ring up the BAEC Gold line (UK or US) and asked them to rebook you on another flight. I have done this while queueing up with the other pax waiting to be rebooked. I then leave the queue if I can sort out what I need to on the phone and re-check in from scratch. I am surprised that no pax around me takes my leads and follows.

However, you cannot do this unless the person at the end of phone can see the cancelled status of the flight. When a plane goes tech after boarding or taken off, they do not always do this. So you maybe stuck in the queue.

The issue here is 2-fold. There is always just 1 (maybe 2) lines at the most with no separate queue for premium pax or status BAEC. It is a first come first serve which is annoying especially for pax who have paid a premium price. The irritating fact here is that the pax at the front of the queue want BA to reschedule all their other connecting flights and a million and one other non urgent issues keeping pax in the queue waiting longer.

BA is no better and no worse than any other airline. Seen the same with AA and VS. with premium pax being downgraded if they did not run to the front of the queue in time. Everytime it happens, you wonder if they could organise it any better - it never changes.

I wont go into whether your bags will be loaded onto the new flight. That is another mine-field. The other half did not see his bag for 3 weeks after one cancelled flight and rebooking to a later one.