So working for BA or an airline as a pilot makes you above the law? I don't think so, sunshine.
Where a criminal offence is proven (innocent until proven guilty) then prosecution of a criminal act is to follow, whether the airline likes it or not.
I see your location indicates that you are not from the UK. Maybe you should study our Air Navigation Order: Part 10: Chapter 1 'Prohibited Behaviour'.
Sussex Police will conduct their own investigation, leading to criminal charges if necessary, with all due respect BA will not get a look in if the guy is remanded!