VS and BA will have an interline agreement in place to allow VS to sell on to BA and viceversa but without codeshare. The issue will be at what rates BA sell their domestic sector to VS and whether that will change once there is only one option available. In the past BD took action in the European court successfully against EI as I recall for refusing to interline, but an increase in price shouldn't be a problem as long as not designed to prevent VS from being able to interline at all. VS costs may therefore increase and they may have to eat the increase to remain competitive. Certainly won't be good news for VS.