BRUpax.....actually the main reason BA pulled off the JFK route was that they weren't flying to a hub which they could fly on from within the States (bi-laterals and all that). BA coudln't compete with AA and CO who have the whole of their US network to feed their BHX services. The vast majority of passengers flying from BHX to the States is to fly on, not to go point-to-point.
Only time will tell as to whether CO will come off but I'd put my money on them holding on.