Staff travel is a non-contractual and discretionary benefit granted at the sole discretion of BA and as such can be withdrawn or varied at the sole discretion of the Company at any time.
I agree to these terms and conditions
Every time you book an ST ticket you agree to these T&C's, there are others, this is the most relevant. So, each time you book a ticket you personally agree that ST is non-contractual and can be removed or varied at BA's sole discretion. I see this as being a very difficult hurdle for UNITE to overcome, particularly as the consequences of putting yourself in breach of contract by striking were clearly defined beforehand.