And that interpretation may turn out to be unlawful.
Nonsense. BA can pro-rate the allocation of a bonus in any way it chooses. The point being made is that if a striker thinks he/she was only on strike for one day, and therefore expects to receive 6/7ths of the bonus, BA may chose to consider strike days plus days after, up to the point that the striker was allocated a trip and returned to duty. Result - a lot less bonus for strikers. And it is
not illegal.
BA can withhold
all of the bonus from strikers, if it chooses to. And it has already stated precisely that for any cabin crew strikers in the forthcoming financial year - strike for one day or five, it doesn't matter - they won't get
any bonus!