The Guardian reports that:
A group of BA flight attendants is claiming that the removal of discounted travel from strikers discriminates indirectly against employees based in Scotland, Ireland and mainland Europe who use the scheme to commute to and from Heathrow airport. The group, called Crew Defence, is representing 75 employees who are lodging cases with an employment tribunal in Reading and plan to sue for compensation if their claim is upheld.
This is a bold claim, but it may be successful in crossing the first hurdle of showing that BA are applying a provision, criteria or practice which is applied equally but puts (for example) Scottish people at a disadvantage. It would then be for BA to show that the treatment is justified. Much will depend on the nature and context of the scheme and its removal. To use an example, if a factory in Carlisle provides a free employee bus from Kendal, can a wannabe employee in Dumfries make a complaint?
The employer is likely to agree that its practice of failing to provide a bus from Dumfries affects far more Scottish people than English, but would argue that it has a legitimate objective (attracting and retaining employees), and it is proportionate to achieve that objective by providing that one bus from Kendal. The employer might well claim, if it is small, that it can only afford the one bus and clearly that bus will either set off in England or set off in Scotland. That itself could constitute justification, but would be bolstered by a rational explanation of why Kendal was chosen in the first place.